hey all, how would i check beam current on a 63 ctc12 clone chassis. im trying to rule out a possible bad crt in my silvertone set being i still cannot get good hv regulation after all has been checked more then twice, and or subbed.

It's called a CRT tester, if you don't have one buy one. But the CRT has nothing to do with HV regulation, I'd look elsewhere.

there is something to be said about this beam current because from what i have gotten here is that if the beam current is to high it will somehow prevent the regulator from working correctly. if its high the hv will be low, and thats what i have and refuses to regulate in the proper way that it was designed to do. the hv and beam current is said that it works together . as for the crt tester, i have 3 of them.

...

ok i had checked the hv current with dark screen hv adjust low and got 1.64 ma and the adjust up was 0.93 ma. so to make this set bloom all i have to do is raise the bias alittle with the r g b drives total counter as they are now. just making sure i have the right wires, the cathode, these are the yellow wires ? if this beam current is to high where would the blame be at this point on this chassis ?

You're barking up the wrong tree, troubleshooting wise.

Actual beam current is an irrelevant figure as far the the CRT is concerned, but it does matter for the regulator. You don't need to know what beam current is to figure this out. If for example you cannot get a full brightness (and not bloomed) image with the regulator out of the picture and the CRT tests good on a reliable checker, you have an issue on either side of the horizontal output transformer or the transformer itself is cooked. In short, you're not making enough HV to drive the CRT hard enough to work correctly. The giveaway is the blooming- if it's happening before you get normal screen brightness, you don't have enough HV or the supply isn't 'stiff' enough. Aka, it lacks current and you should investigate the oscillator, tubes and flyback. If that's not it the HV rectifier may be weak, the flyback may be past its prime, or you have some serious leakage to deal with somewhere. If it's a smoker set, remove and clean everything with HV on it. Believe me when I say, you will throw up at what comes off...

If on the other hand you can't get full brightness without blooming and you know the horizontal section is good, the CRT is probably gassey enough to cause excess current drain but elude detection on a CRT tester- ask me how I know this is possible...


My guess? You probably have a bad picture tube (gassey), and you need to sub another one to confirm. Appearance of shiney getters is not a reliable indication the tube hasn't gone gassey- again, ask me how I know. You need to be methodical about eliminating one thing at a time, or you'll never find the problem. I'll give you a hint- you only need just over 1ma to get a decent picture with north of 20kv on the CRT.

Don't rule out a bad HV rectifier. Also, if there is a current limiting resistor for the HV rectifier filament, check it as its resistance may have gone up.

If you pull the CRT socket and the HV comes up and can be controlled properly by the regulator then that may prove a gassy CRT.

well ok it all makes sense but this set has a new fly, tried several rectifier tubes, cathode currant 190ma, several regulator tubes, and the rgb drives must be kept counter clock all the way because if i set the drives and having to use the bias alittle to set the drives then normal operation causes blooming and during the blooming the hv dips to sometimes 18-19 kv not enough really bad on white scenes. the brightness is all the way up and it does give a nice picture but it seems with the loss or not enough hv scenes will change color as it blooms. i had watched the hv dip on white scenes and wont go up untill the white changes. this tv was from a non smokers house which is a plus,lol. i have a dvom that checks frequency so is there a way i can check the frequency by probing a specific pin somewhere on the chassis to get an idea what it may be and then again what should the frequency be. the vert holds and the horiz hold is good also if its any indication. all the under chassis caps were changed in and around the horiz section also, nothing i ever done to the set will fix the hv i cant believe i may be missing something here. caps were changed on the vert board never a change for the good. it really is lacking hv and it makes it harder to set it up correctly without enough hv. the lack of enough hv is still unknow to me weather its a bad crt or something else i dont know but would like to get to the bottom of it once and for all. but the brightness is all the way up but its not as bright as it should be because the drives are low because of the lack of hv but even little changes in the scenes will pull the picture in on the right side alittle. if memory serves i think when i took the crt plug off the hv barely made it to the 22-23 kv mark with the adjust maxed clockwise and with the reg cap off the hv climbed to over 30kv. in other posts i had posted a pic of a mark on the crt starting at the anode button extending down the bulb about 6 inches just to the dag on the outside but the mark is inside the bulb where i thought maybe the interior dag was burned off in that area causing these problems but all and all i dont know.

Only way to know for sure is run another CRT with this chassis, if things work as they should the CRT is bad.

yes it would rule alot of things out as i do have other sets with good crts but would have to take apart 2 sets, oh well...

seeing as it takes at most 10 min to pull a chassis on these simple sets, that seems a lot more logical than more test and part changes.

yes thats true but with limited room that i have makes it alittle more difficult but ill have to do it. to bad i didnt have a spare in the closet,lol lol. but in the end the sets will have to be set up again when put back together, if only there was a way to tell if there is a gassy problem with this crt i would do it. i tried the crt tester in the cutoff mode and it has been said that if there is gas present it will show something of color in the neck but i have done that already in the dark and nothing there.

I am guessing there is gassy as in neck glow purple in which case CRT will not work at all, then there is gassy where CRT just does not perform correct. The way to know for sure is trying the chassis on another known working set. No more need to guess whats wrong. swapping is the way to go.

Did you ever check L14 (coil from service switch to cathode leads of crt) that I mentioned many many post and threads ago? if the swap shows the issue is with the chassis and not the CRT I would suggest you check that while the chassis is out.

...

Did you ever check L14 (coil from service switch to cathode leads of crt) that I mentioned many many post and threads ago? if the swap shows the issue is with the chassis and not the CRT I would suggest you check that while the chassis is out.

yes i did check L14 the ohms, compaired to the sams. if im correct i didnt cut it from the circuit i just measured the ohms and it was where it should be so i didnt feel i should remove it from the circuit.

Does the HV remain constant until the regulator current drops to zero as you increase the brightness? If it doesn't, the HV regulator isn't doing its job. Blooming shouldn't start until the regulator current goes to zero.

If the regulator behaves, but it doesn't produce a bright picture at maximum beam current before blooming the CRT almost has to be bad.

the hv stays steady depending on the scene being shown on the screen because white scenes are the worst as during white scenes the hv drops and wont regulate to maintain until the white changes to some other colors. the brightness is always at max, but heres the kicker the blooming is so much worse if i do the grey scale the way it is said to do by putting in service mode and what ever color dont show up i would have to use the bias alittle and adjusting the rgb drives per the sams. this is when the blooming occurs so i have to leave the bias counter and the rgb drives counter in order to get any decent picture, and the white scenes are still a problem setting it up this way. so the result is a somewhat not bright picture although clear its not right. i didnt watch the ma during all of this but this is when it blooms as it seems to when a bigger demand is placed on the crt by raising the drives and or the crt bias, it cannot handle it as it will bloom and pull in on the right side screen. if i turn the brightness down and then turn it back up it does not bloom provided the rgb drives and the bias is fully counter clock.

You have a HV problem, then. Start looking at the horizontal section or HV rectifier.

...

Perhaps the HV reg resistors or caps that tested good on low voltage test equipment break down and stop working at rated voltage.

well i already tried a solid state 3a3 rectifier, no difference. i also checked the hv regulator resistors and they checked at 1.6m and 1.59 close enough to 1.5 meg. the funny thing is first getting this set from the beginning the hv was a problem so since then i changed all the caps under the chassis with no change in the hv regulation including the flyback. i thought i found the problem when i changed the fly when i found the focus 1v2 was wired wrong but that didnt help after correcting that. i had thought there was a problem somewhere in the crt drive circuit chroma board or somewhere else affecting the regulation of the hv but im all out of options as to where to look. i was trying to cover as much as possible befor pulling the crt and swapping to rule it out because i am limited to room here and yet the crt in the set tests very good for the age.

...

lol,lol, thats just it i dont know anymore whats going on with the set. and yes i have to swap the crt and if another crt does the trick then ill be amazed at what may be wrong with the other seeing as it tests great. but it could be alittle gassy enough to create this problem and that would be a real shame because it does test good.

My guess? You probably have a bad picture tube (gassey), and you need to sub another one to confirm.

They can test good and be gassey...

well with my on going hv issue with this set i do have a question. with the set on hv present at anode crt plug off should there be any voltage at any of the crt pins. i checked with a dvom to ground and have no voltage at all except at the focus pin which was 7 volts , would this sound right ? and the hv with the anode wire off the crt is 19kv just at the wire. anode wire back on, crt plug off i was lucky to get 22 kv, thats it, picture scene changes and will dip right down to 19 kv or less. i didnt try another crt yet but was looking around for something concrete here that may give me an idea the crt is finished maybe due to gas. i read an article online about crts and what was said about getters is that a bright shiney mirror like getter is good no air or gas. however what also was said was that a white of course means it took on air but the last was a getter that is coal black no mirror shine at all indicates gas in the tube. has anyone heard of this coal black getter meaning a gassy crt ?

Unless white there is no sure indicator, looking at getthers, of gas.

Well if it's 19kv with no load, you've got a chassis problem. It should shoot up to the setpoint of the shunt regulator and stay there with no CRT attached, does the HV pot do anything in that state?

Well if it's 19kv with no load, you've got a chassis problem. It should shoot up to the setpoint of the shunt regulator and stay there with no CRT attached, does the HV pot do anything in that state? the hv pot adjust does seem to work but to get even 19kv the pot has to be maxed. there is nothing else i can seem to look at as i looked at what seems to be everything already and have not found anything wrong. so if its a chassis problem then i am overlooking something here. or it is infact the crt. i thought the hv without connected to a crt will be limited because the crt acts like a capacitor so being off the crt 19kv sounds maybe like thats all i would get, i dont know at this point. but then again hooked back up to the crt i would think it would shoot up but didnt. does anyone know the leads that come of the hv regulator tube as to which one if there is a specific lead that does the triggering of the regulation, maybe a specific lead from that tube i can trace if this lead is used as some kind of reference for the hv regulation. because this hv just sits dont raise up just dips as if there were such a wire were cut.

the HV adj should not "seem to work" it should work, in a very linear fashion.

Disconnect the pot from the circuit and confirm (preferably with an analog ohm meter) that it is working as it should (500k to near 0 resistance as you adjust).

Confirm the voltage readings at the shunt tube grid and cathode, make sure the grid varies with the pot.

Confirm the total bias of the shunt tube is within specs of the sams.

At some point I recall you saying the HV would go to 30kv with out the CRT anode attached.

If now you are saying the max is 19kv without the CRT attached then only 3 things can be wrong.


Remember you are working with high voltages all over the place (400v around the cathode and grid of the shunt, 30kv at the anode) so be careful.

1) bad shunt tube

2) bad shunt tube bias

3)no loner getting 30kv with shunt tube disconnected.

the HV adj should not "seem to work" it should work, in a very linear fashion.

Disconnect the pot from the circuit and confirm (preferably with an analog ohm meter) that it is working as it should (500k to near 0 resistance as you adjust).

Confirm the voltage readings at the shunt tube grid and cathode, make sure the grid varies with the pot.

Confirm the total bias of the shunt tube is within specs of the sams.

At some point I recall you saying the HV would go to 30kv with out the CRT anode attached.

If now you are saying the max is 19kv without the CRT attached then only 3 things can be wrong.


Remember you are working with high voltages all over the place (400v around the cathode and grid of the shunt, 30kv at the anode) so be careful.

1) bad shunt tube

2) bad shunt tube bias

3)no loner getting 30kv with shunt tube disconnected.

this set is nuts, lol, lol, the 30kv was with the shunt tube cap off. i have tried 4 shunt tubes all had the same result , no change. as for the voltages at the shunt tube they were where they should be. and 19kv was with the anode wire off the crt. as well as the currant too was ok. i had unsoldered the pot and checked the ohms and again was good.

lets break it down

all the following with CRT anode off to take the CRT out of it.

shunt cap off
30kv at anode lead

shunt cap on
19kv to 22kv

HV setting to max

so the shunt is drawing current with pot a the max HV setting

two things can cause it to draw excessive current

1)bad shunt tube (gassy/grid emissions), replace with a KNOWN working one.

2)incorrect bias (voltage divider resistors/pot)
leakying cathode/grid cap on shunt tube (upsetting the bias as well).

It has to be one of the above.

Did you alter any wiring around the shunt? does the cathode resistance to ground change the the HV pot?
do you have resistance checks for the tube pins on the shunt.
did you REPLACE the grid to cathode cap on the shunt? if so did you make sure the replacement cap was good?

I wonder if your HV reg tube socket is making proper contact with the tube pins? If not that would explain correct voltage at the socket, but incorrect behavior of the tube.

19kv with the HV pot maxed and the cry disconnected means a shunt regulator problem, does it have one of those 100meg resistors in the circuit somewhere? Might have drifted. You need to take readings of the regulator tube cathode and grid, post them here. The bias on the regulator is certainly funny...it's dragging your HV down for some reason.

lets break it down

all the following with CRT anode off to take the CRT out of it.

shunt cap off
30kv at anode lead

shunt cap on
19kv to 22kv

HV setting to max

so the shunt is drawing current with pot a the max HV setting

two things can cause it to draw excessive current

1)bad shunt tube (gassy/grid emissions), replace with a KNOWN working one.

2)incorrect bias (voltage divider resistors/pot)
leakying cathode/grid cap on shunt tube (upsetting the bias as well).

It has to be one of the above.

Did you alter any wiring around the shunt? does the cathode resistance to ground change the the HV pot?
do you have resistance checks for the tube pins on the shunt.
did you REPLACE the grid to cathode cap on the shunt? if so did you make sure the replacement cap was good?

ok your right so far but the reg tube i had tried working ones, known working i didnt alter anything at all in the set and the cap i think you are talking about cathode cap i believe it was a disc cap and i got one from moyers but it looked to small even though it was marked as the right one i still had no luck so i found on ebay nos caps and put that one in, was like the original i had changed in the first place. i have the ma specs in earlier posts on the regulator and they appeared ok to a member, it my have been you. you mention voltage divider resistors, where exactly are they? if its the high wattage ones around the hv pot i already did check them. i dont remember if i did resistance checks on the hv reg tube but i do believe i did because i do remember doing all of the others taking awhile to do so.:drool: so i dont think i would have left that one out.

I wonder if your HV reg tube socket is making proper contact with the tube pins? If not that would explain correct voltage at the socket, but incorrect behavior of the tube.

is it possible the wire burned inside the insulation ? if it did then i would pull the wire slightly and if it stretches then that could be it so ill look into that. the pins look very good and the tube fits tight in the socket, but i could check that again.

19kv with the HV pot maxed and the cry disconnected means a shunt regulator problem, does it have one of those 100meg resistors in the circuit somewhere? Might have drifted. You need to take readings of the regulator tube cathode and grid, post them here. The bias on the regulator is certainly funny...it's dragging your HV down for some reason. it has 2- 1.5 meg resistors and i checked them and they drifted very little 1.6 and 1.59 not so bad within range. i already posted the voltage findings:drool: and the ma from all the few wires coming off the 6bk4 reg tube. please check further back on this thread for the voltages they are here. i think there were a brown wire, a green wire and i think a yellow coming off that tube.

I think you should try switching places of those 2 1.5meg ohm resistors......

Turn the horiz centering control.... Does it do anything....? What exactly does it do....?

Turn the focus control, do you have a range on it....? Does it do a lot, or not....?

.

A long shot but there is usually a low ohm resistor
in the HV rect filament inside the HV cup. Also if you unplug the CRT
socket does the HV come up ? May have been covered but the thread is
getting long !
And dont forget the H. blanking tube, causes all sorts of odd problems.

73 Zeno:smoke:

I think you should try switching places of those 2 1.5meg ohm resistors......

Turn the horiz centering control.... Does it do anything....? What exactly does it do....?

Turn the focus control, do you have a range on it....? Does it do a lot, or not....?

.the horiz centering control is just about all the way to one side it will swing from one side to another but to center the screen the pot is all the way to one side. the focus does have range although it could be a bit clearer. and the 1.5 meg resistors i was going to try 2- 1 meg resistors but that i think will only kind of change the pot position from maybe maxed to the half mark.

A long shot but there is usually a low ohm resistor
in the HV rect filament inside the HV cup. Also if you unplug the CRT
socket does the HV come up ? May have been covered but the thread is
getting long !
And dont forget the H. blanking tube, causes all sorts of odd problems.

73 Zeno:smoke:

i think i tried another blanker tube with no change and there is no resistor on the hv rec socket. the crt plug off only comes up alittle bit.:smoke:

Well changing the resistors from 1.5 to 1.0 would not do much.... I figured if they
were off, like the one you said was 1.5 and the other 1.6 and the pot .5 meg, then
it may have changed the range of HV if it shifted the bias on the grid of HV Reg.

So, with no plug on end of crt, hv changes by how much...?

And no HV lead attached to tube HV goes to how much...?

Can you make both of those readings again with no other work done in between...?

And one more.... HV connected, Plug on tube.... Brightness at cutoff - Dark Screen..... What id HV.....?

Make each of these tests with the HV adjusted to MAX.....

And write out each reading, and condition for the reading....
Acceptable answers are not "same as before" and or "they are good".
We need the condition, and the value - please.


And the cap between the grid and cathode of HV reg, you replaced that one....?

Anyone got an objection to running the set without that cap for a test...?
Just in case it's not working at that high voltage....

As a matter of fact, you should make these tests on both your sets with the same
chassis, or allow someone with the same set chassis to do them and have an
ongoing comparison..... And for each of these tests, please also record
the B+ Boost..... I think it's 390V.....


.

Well changing the resistors from 1.5 to 1.0 would not do much.... I figured if they
were off, like the one you said was 1.5 and the other 1.6 and the pot .5 meg, then
it may have changed the range of HV if it shifted the bias on the grid of HV Reg.

So, with no plug on end of crt, hv changes by how much...?

And no HV lead attached to tube HV goes to how much...?

Can you make both of those readings again with no other work done in between...?

And one more.... HV connected, Plug on tube.... Brightness at cutoff - Dark Screen..... What id HV.....?

Make each of these tests with the HV adjusted to MAX.....

And write out each reading, and condition for the reading....
Acceptable answers are not "same as before" and or "they are good".
We need the condition, and the value - please.


And the cap between the grid and cathode of HV reg, you replaced that one....?

Anyone got an objection to running the set without that cap for a test...?
Just in case it's not working at that high voltage....

.hv without the crt is 19kv adjustable by the pot but 19 at max. hv with crt 22kv adjustable by pot at max. the cap you are talking about is the 033 i think and was changed a few times with new ones. at the cap that is the place for the jumper for the hv current and with that jumper section open with no meter in between the hv will not adjust by the pot and it goes over 30kv. brightness down dark screen the hv is between 22-23kv hv pot maxed brightness up the hv drops more so depending on whats on the screen. the b+ is in place it is good that was the first thing i ever did check and i find myself still checking it, lol,lol...

And what are the voltages at pin 1 and pin 5 of the 6BK4 Shunt when the HV adjust
is at min, and max....?

.

And what are the voltages at pin 1 and pin 5 of the 6BK4 Shunt when the HV adjust
is at min, and max....?

.6bk4 reg tube pin 1 402 volts and pin 5 390 volts but i dont remember if the bright was down when i had checked it as i hope this helps.hv current dark screen hv pot low 1.64 pot high 0.93 bright up pot low 1.16 pot high 0.20

If you mean .93ma with a dark screen and HV set to max, that's your problem. Most of the Sams I've read for roundies specify .8ma with a dark screen, HV set to whatever the schematic calls for. If you're pulling any more than that, chances are you're getting close to melting the 6BK4 as you're likely exceeding it's dissipation. You see HV schematic information has more to to with the regulator tube than it does the chassis.

For example, the 6BK4B (which is what most will have in their chassis) is rated at 40 maximum plate watts. Taking into account a 20% tolerance, this tube can be expected to dissipate somewhere around 32 watts continuously. Typically it comes to around 25 watts though, RCA designed the shunt circuit conservatively to maximize the shunt tube's life.

So for your example with a dark screen and the HV pot at 'low' and drawing 1.64ma (assuming a 23kv anode), that comes to 37.7 watts- easily above what RCA would have designed it to do, and dangerously close to the tube's maximum dissipation. I strongly suspect that if you look at the tube's structure under those conditions with a darkened room, you'll see the plate glowing which can be seen reflected off the bottom part of its structure (the part containing the grid and cathode, it's usually shiny so you can see stuff in it).

For the other example: .93ma@23kv=21 watts which is much better but again, outside what I would consider normal for a shunt tube which should be closer to .8ma. Obviously whenever you have something on screen, shunt current should drop as the CRT beam current picks up where the regulator left off. You should check to make sure the shunt tube's cathode current drops as brightness increases, if not the regulator circuit is suspect. Also take a look at your B+boost voltages, as that's where your regulator is taking its reference voltage from. If B+boost is jacked, so will regulator cathode current as the grid receives it's marching orders from whatever B+boost is doing.

Yah, miniman hit it with what I was looking for, the bias in the tube is pretty high....

For the other example: .93ma@23kv=21 watts which is much better but
again, outside what I would consider normal for a shunt tube which should be
closer to .8ma. Obviously whenever you have something on screen, shunt
current should drop as the CRT beam current picks up where the regulator left
off. You should check to make sure the shunt tube's cathode current drops as
brightness increases, if not the regulator circuit is suspect. Also take a look at
your B+boost voltages, as that's where your regulator is taking its reference
voltage from. If B+boost is jacked, so will regulator cathode current as the
grid receives it's marching orders from whatever B+boost is doing.


I was going to ask about those current readings, are they ma. and how accurate
do you think your meter is...?
Also that voltage I asked about B+ Boost, you did not post a number...?
You need to measure these things today, not look up your old posts, we need
to clarify exactly what is happening.... Your B+ Boost could be too high, this could
be why the voltages at the reg. are higher than the schematic says they should be...

.

If you mean .93ma with a dark screen and HV set to max, that's your problem. Most of the Sams I've read for roundies specify .8ma with a dark screen, HV set to whatever the schematic calls for. If you're pulling any more than that, chances are you're getting close to melting the 6BK4 as you're likely exceeding it's dissipation. You see HV schematic information has more to to with the regulator tube than it does the chassis.

For example, the 6BK4B (which is what most will have in their chassis) is rated at 40 maximum plate watts. Taking into account a 20% tolerance, this tube can be expected to dissipate somewhere around 32 watts continuously. Typically it comes to around 25 watts though, RCA designed the shunt circuit conservatively to maximize the shunt tube's life.

So for your example with a dark screen and the HV pot at 'low' and drawing 1.64ma (assuming a 23kv anode), that comes to 37.7 watts- easily above what RCA would have designed it to do, and dangerously close to the tube's maximum dissipation. I strongly suspect that if you look at the tube's structure under those conditions with a darkened room, you'll see the plate glowing which can be seen reflected off the bottom part of its structure (the part containing the grid and cathode, it's usually shiny so you can see stuff in it).

For the other example: .93ma@23kv=21 watts which is much better but again, outside what I would consider normal for a shunt tube which should be closer to .8ma. Obviously whenever you have something on screen, shunt current should drop as the CRT beam current picks up where the regulator left off. You should check to make sure the shunt tube's cathode current drops as brightness increases, if not the regulator circuit is suspect. Also take a look at your B+boost voltages, as that's where your regulator is taking its reference voltage from. If B+boost is jacked, so will regulator cathode current as the grid receives it's marching orders from whatever B+boost is doing.

dark screen brightness down hv pot set to min, ma is 1.64 hv pot max , 0.93 brightness up hv pot set to min 1.16 hv pot set to max 0.20 and the dvom i use i do trust it i did compare with another meter to be certain. the 6bk4 dont even get all that hot to the point of melting, no where near. i cannot get 23kv even to stay for a moment. i will have to check the exact b+ voltage under a load, where would the best place be to take this reading at this point ? and yes this is milli amps. the sams show the voltages and they are not far off it seems to me unless 5-10 volts would make a world of difference, i dont know.

The current seems high as miniman explained. And since the reg is working off b+boost
we will have to figure it out... We're trying with the clues we have.... I got one
of the rca schematics off the internet, it says 390v and 376v to grid of 6bk4, you
have 402, and 390V grid I believe.... So lets look at your B+ voltages.....
Check them right off the caps in the PS.... 405V-c125 160mfd.,
386V - c120A 80mfd, and I think the last was 276V c-120b 50mfd.

Does your schematic have a total current for the HV output...?
as in picture tube plus HV reg....? and an acceptable way to
determine total....? As per sams.... to be accurate...



.

Sure would be easier to follow this thread if there were some daggone punctuation... :smoke:


From what I gather, the regulator seems to be working as it should. You said you put a new fly in it? You probably wired it wrong, there's no reason for HV to be drooping like this.

The current seems high as miniman explained. And since the reg is working off b+boost
we will have to figure it out... We're trying with the clues we have.... I got one
of the rca schematics off the internet, it says 390v and 376v to grid of 6bk4, you
have 402, and 390V grid I believe.... So lets look at your B+ voltages.....
Check them right off the caps in the PS.... 405V-c125 160mfd.,
386V - c120A 80mfd, and I think the last was 276V c-120b 50mfd.

Does your schematic have a total current for the HV output...?
as in picture tube plus HV reg....? and an acceptable way to
determine total....? As per sams.... to be accurate...


ok this chassis is a clone and i have the sams for it and i show 370 and 385 and yes the voltages i posted have not changed and they are kind off high, i think around 15 volts. and the highest on the b+ is 400 volts and 390 volts and i knmow it was right but i will check it again to be certain this time and i will write everything down. the sams shows that the hv regulator current should not be less then 850 microamperes . it says to adjust to 23kv but i cannot get it there. he suggested in the first paragraph that the hv pot was maxed but it was not it was counter clock so thats why i put the specs up again. other then the voltages the other is ma.:scratch2:
.
omg this set

:smoke:Sure would be easier to follow this thread if there were some daggone punctuation... :smoke:


From what I gather, the regulator seems to be working as it should. You said you put a new fly in it? You probably wired it wrong, there's no reason for HV to be drooping like this. yes it is a new flyback and this set always had a hv issue but i thought i had found the problem when i changed the fly i discovered the 1v2 was wired wrong and since correcting that the focus voltage and the overall focus had much improved. i found the mistake and corrected it and checked other areas for other mistakes and having the sams i was able to check areas and fix the wiring mistake. i also double checked all the work i had done by the sams and found none.

Sure would be easier to follow this thread if there were some daggone punctuation... :smoke:


From what I gather, the regulator seems to be working as it should. You said you put a new fly in it? You probably wired it wrong, there's no reason for HV to be drooping like this.

Yes, he said new fly, and he rewired the focus circuit because something was wrong...
I thought something may be wired wrong too, that is why I asked the questions
about Horiz. Centering, and focus the other day... I figure if they work, and have
some reasonable range, then maybe there is no mistake...... In one of the
earlier threads I also asked about the new fly, and if all the contact points
were correct, or if there were mods on any install note sheet....

It would be cool if someone with recent experience on this chassis takes the point....

That reg. circuit is too simple to be causing all this trouble....

.

Yes, he said new fly, and he rewired the focus circuit because something was wrong...
I thought something may be wired wrong too, that is why I asked the questions
about Horiz. Centering, and focus the other day... I figure if they work, and have
some reasonable range, then maybe there is no mistake...... In one of the
earlier threads I also asked about the new fly, and if all the contact points
were correct, or if there were mods on any install note sheet....

It would be cool if someone with recent experience on this chassis takes the point....

That reg. circuit is too simple to be causing all this trouble....

.

well there were no mods or special notes in this set. the hv reg does look simple but i have this set for 2 years plus and was never able to find whats going on with it . so i might just as well try the crt from my other set because of the mark on the inside of the glass on the crt thats in the set now was not there when i first got it but over a small amount of time this set has on it since i have the mark appeared so maybe the interior dag somehow is damaged and causing all of this i dont know but ill have to rule it out once and for all.

Can you post a picture.....? I'm gunna say I don't think you have any inside tube
coating problem.... You would have arcing, or some other problems.... Just not sure....

.

Can you post a picture.....? I'm gunna say I don't think you have any inside tube
coating problem.... You would have arcing, or some other problems.... Just not sure....

. my computer that has the pic of the mark on the inside of the crt i cant use it at this moment but it is here on karma under 21fbp22 crt there is a good pic of it. let me know if you cant find it.

the pic of the crt is on page 6 under gassy 21fbp22

I remember it now..... I'm not concerned about it.... Don't think it's a problem...

.

well i dont know at this point, but i do really appreciate the help from all the members here and i do try but at the same time i was never a tv tech and i really im sorry for driving everyone here crazy with this nutty silvertone.

Well, since you got this set with HV problems, and found some wiring mistakes in the
focus area, you should take a few steps to ensure that no problems were introduced
be work done by someone else..... I think you should get, or borrow a good camera,
take pictures of the flyback, the wiring, and under the chassis, post good clear picts, and
some the focus wiring you found and repaired.... There are people here who have
recently worked on and own several of them.....

You might also find that if both of your sets are identical, as far as the chassis goes,
that visual comparison might be a very good idea.... I'm confident the problem can
be found, there are lots of people here who know this chassis inside out....

By the way, which Silvertone is this one.... 63, or 65...? And are they the same.....


.

I am curious about a few things.
1. where and how are you measuring the regulator current?
2 what is the actual B+Boost voltage? Should be ~1000 - 1200volts if I recall correctly.
3. Have you checked the screen grid resistors in the Horizontal output tube. I think there is a 47 ohm and 13K ohm that if they drift high at voltage cause low High voltage.
One thing that bothers me is that all the controls seem to have to be at one end of their range. This indicates a voltage problem in the B+ or Boost voltage. Possibly not enough drive from the horizontal output stage.
4. Have you checked for leaky caps in the horizontal yoke windings?
The 1.5 meg resistors in the regulator circuit are a matched pair. I would not change them to different values. Since they are 20% they are not out of spec. The key is they should be the same value. Yours are about 7% high, but they are very close to the same value.

Enter ye the 10th circle of hell,

Timmy CTC-12 clone HV regulation.

I also double checked all the work i had done by the sams and found none.

Sams can have mistakes, bounce the schematic against an RCA one?

Well, since you got this set with HV problems, and found some wiring mistakes in the
focus area, you should take a few steps to ensure that no problems were introduced
be work done by someone else..... I think you should get, or borrow a good camera,
take pictures of the flyback, the wiring, and under the chassis, post good clear picts, and
some the focus wiring you found and repaired.... There are people here who have
recently worked on and own several of them.....

You might also find that if both of your sets are identical, as far as the chassis goes,
that visual comparison might be a very good idea.... I'm confident the problem can
be found, there are lots of people here who know this chassis inside out....

By the way, which Silvertone is this one.... 63, or 65...? And are they the same.....


.the silvertone is the pic you see on this page its a 1963. the other ones i have are 65 silvertone and it has a different focus circuit. and besides i have went over this set with the sams hoping to find a mistake by another tech but have yet to find anything other then the focus circuit. and the other is 65 maggie which has a problem as well and that one has the 2v2 circuit. the only thing i can say is when i got the set i changed the focus coil because it had a burn mark so i assumed it was bad and after putting the new one in befor finding the focus miswire the focus was not good at all. so i took it out only to find that one part of the coil had opened so now i couldnt use it anymore and moyers sold me the last one. i then checked the ohms of the old coil and to my surprise up against the sams and it was good but i dont know what the history was to have burned the coil the way that it did but it was still good so i put it back in with a new resistor i think it was 100k because the old one was burned clear apart and its been in there since. even though the ohms check good im not sure if this may be a cause for the hv problem. one other thing i remember is in first getting the set going the horiz hold was all the way to one end so what i had done to correct that was tweeked the coil on the vert board and that fixed that and now it has range left and right to adjust if need be as befor it didnt. sorry for the edits but i did have arcing at the neck somewhere under the yoke when i first got it going but this may hjave been when i took off the reg tube cap to check hv at the time but never did arc again since.

I am curious about a few things.
1. where and how are you measuring the regulator current?
2 what is the actual B+Boost voltage? Should be ~1000 - 1200volts if I recall correctly.
3. Have you checked the screen grid resistors in the Horizontal output tube. I think there is a 47 ohm and 13K ohm that if they drift high at voltage cause low High voltage.
One thing that bothers me is that all the controls seem to have to be at one end of their range. This indicates a voltage problem in the B+ or Boost voltage. Possibly not enough drive from the horizontal output stage.
4. Have you checked for leaky caps in the horizontal yoke windings?
The 1.5 meg resistors in the regulator circuit are a matched pair. I would not change them to different values. Since they are 20% they are not out of spec. The key is they should be the same value. Yours are about 7% high, but they are very close to the same value.i measured the hv current at the jumper location at the 033 cap and i used a fluke dvom and i do trust it works fine. i checked any and all resistors at the base of the hot and they are fine. the sams says the b+ voltages the highest is 400 and 390 volts and other lower ones right off the caps in the PS. the b+ is up because i would not be able to get the voltages at the crt that i get and they would be low but at around 700 volts at the crt seems the b+ is ok. the only thing i did not do is check or change caps in the yoke but i did write it down as something to check. i also had double checked my work with any resistors or caps that i had done which i had changed caps under the chassis only because of this problem and also unsoldered the caps and check them the simple way with a meter and they looked fine thinking maybe i got a bad one or 2. i have a new meter that checks, NF,MFD in caps and also frequency but dont know yet if it goes as high as 15,730.

Hey, Had a black-out for a few hours this morning... Someone took their pickup a few
quarts of alcohol and went out to get some wood........ Now we got 2 phone poles
on this street cut in half and hangin in the air....

Bill is right about the H-output tube screen voltages, I'm not sure but I think we went over it
before on another thread.... But you better check, the 47ohm, and 13K resistor off pin
4-8 of 6dq5 also suppose to be around 145V there....
My schematic don't have the number, but off the cathode of the damper tube somewhere
should be a test point for B+ Boost, and it should be around 1KV like bill said... Check your
Sams it may have a test point and a number.... 1Kv ~ 1200V ??

Also, since you said you are not a tech, I want to be sure you are aware B+, and B+ Boost
are two different things.... B+ Boost does not come off the power supply section of the tv, it
is part of the voltage from the horiz. output section of the tv..... Generated off the Damper
tube.... They may have a point where they show a test spot, and a Voltage number, so use their
test point....

Did you check or replace the caps on the yoke... C 105 ?? Good one to look at....

.

Hey, Had a black-out for a few hours this morning... Someone took their pickup a few
quarts of alcohol and went out to get some wood........ Now we got 2 phone poles
on this street cut in half and hangin in the air....

Bill is right about the H-output tube screen voltages, I'm not sure but I think we went over it
before on another thread.... But you better check, the 47ohm, and 13K resistor off pin
4-8 of 6dq5 also suppose to be around 145V there....
My schematic don't have the number, but off the cathode of the damper tube somewhere
should be a test point for B+ Boost, and it should be around 1KV like bill said... Check your
Sams it may have a test point and a number.... 1Kv ~ 1200V ??

Also, since you said you are not a tech, I want to be sure you are aware B+, and B+ Boost
are two different things.... B+ Boost does not come off the power supply section of the tv, it
is part of the voltage from the horiz. output section of the tv..... Generated off the Damper
tube.... They may have a point where they show a test spot, and a Voltage number, so use their
test point....

Did you check or replace the caps on the yoke... C 105 ?? Good one to look at....

. ok, the 2 resistors of the 6dq5 have been double checked and are ok. the b+ voltages and the boost voltages i know are from different places and i hope the sams shows a test point for the boost voltage. straight b+ i know comes first from the transformer to the diodes then to the caps. i do have alot of tv experence with the new garbage, smd and so on. i know this chassis dont have a boost diode so ill hope to find a test point at the damper for this boost voltage. i was looking at the rca schematic and c105 is one that is there and ill check that. i also know what the doubler caps do ,lol,lol so i do understand...:yes: and the screen voltage at the hot pins 4-8 142 volts and pins 1-5 -56

those 2 resistors are 100 ohm and a 47 ohm at the hot , i think i replaced the 100 ohm after getting the set and recapping as i went over this and found that resistor drifted very little and probably didnt even have to change it. just checked the sams it shows pin 2-7 385 volts pin 9 is the one with the hv and it says do not measure. im showing only a 720 v boost source but that dont tell it all.

This pic shows B+ Boost, where it's made, but not necessarily where
to measure it.....

And the screen grid resistors.

.

This pic shows B+ Boost, where it's made, but not necessarily where
to measure it.....

And the screen grid resistors.

. ok yes i have the same here but this sams is alittle different by the numbers your 3 is my 9 but same location. ok the 13k 7 watt i probably checked that one already but i will again. so now ill have to find out where to test this boost voltage because i believe i hit that spot already by accident and burned another fluke dvom out so i dont want to do that again.

NO - be careful, there are very high voltage spikes there ! !

.

my mistake there is no c105 in the yoke the sams i have dont show it nor does the rca schematic but shows it in the color board as a disc cap. the yoke appears to have c 123 caps

horz pos pot wired right, not open?

horiz pot new and wired, came with the fly.

I don't know for sure on your set, but on CTC-15 clones I have the boost supplies the high voltage side of the CRT screen/G2 potentiometers, and IIRC the vertical linearity control pot.

On my Silvertone CTC-15 clone there was an SS boost diode that was bad when I repaired my set. Your set may be the same or different so take this with a grain of salt.

I don't know for sure on your set, but on CTC-15 clones I have the boost supplies the high voltage side of the CRT screen/G2 potentiometers, and IIRC the vertical linearity control pot.

On my Silvertone CTC-15 clone there was an SS boost diode that was bad when I repaired my set. Your set may be the same or different so take this with a grain of salt. i think my other silvertone has that diode but not this old 63 , boy for a freebie this set has been truly a thorn in my side for sure,lol..:tears:

does the focus voltage vary from about 4k to 5k, I use a simpson 260 to check.

Its easy to miss wire a focus coil.

in focus, the voltage is just befor 5kv and yes it will vary and i looked at the sams for the position of the taps to make sure i had it right. wired wrong may give all this headache.

it should very about 1kv
you have to becareful about those focus coils, often they are generic replacements with extra lugs or lugs that are in different orders. Generally you use the included instructions when replacing. they are variable transformers that vary both phase and amplitude adding or subtracting from the voltage going to the focus tube.

what was the problem with the orig FLY?

there was no problem with the old fly i had a new one and decided to change it thinking the fly was the problem with the hv, but it made no difference.

Use the HV probe to check the B+Boost, or a VTVM. Most DVOM meters do not measure a high enough voltage. I use an RCA Senior voltohmist VTVM on the 1500 volt scale. Boosted B+ is used for the high voltage side of the screen controls and the vert height and vert lin, as well as horizontal centering.

If the 13K resistor that is in series with the 47 ohm resistor has drifted high it will cause the HV to be low. You may have to raise the HOT cathode current a little. Maybe to 200ma. Lower is better, but it must stay under 210ma.

Use the HV probe to check the B+Boost, or a VTVM. Most DVOM meters do not measure a high enough voltage. I use an RCA Senior voltohmist VTVM on the 1500 volt scale. Boosted B+ is used for the high voltage side of the screen controls and the vert height and vert lin, as well as horizontal centering.

If the 13K resistor that is in series with the 47 ohm resistor has drifted high it will cause the HV to be low. You may have to raise the HOT cathode current a little. Maybe to 200ma. Lower is better, but it must stay under 210ma.ok then the next step will be to check that 13k resistor and if its good then move on to the boosted voltage at the damper and ill use the hv probe. if the voltage is higher at the damper befor L30 but lower after then L30 may be bad so ill check the ohms on that .4 ohms. if this voltage is high then ill move to check caps in the yoke.

Timmy; Be aware that coils, and capacitors act on the signals coming through them so
to speak.... The raw DC off the damper is pulsed at 15K/cps. The voltage needs to be measured
at a point specified by the schematic. There is no way of knowing what is at the Damper
cathode, and no way of knowing what it's going to do to your test equipment....


Or if it's going to read it correctly....

My schematic is only that, I don't have a full service manual, and do not own a set like that,
or have recent experience on it.... SO be careful... Only use the HV probe.... ***

But There may be some validity in checking around there.... Because you say that you have
had retrace lines on the screen.... And I remember you saying something about how the
screen controls are set..... Do you always have retrace lines on the screen, no matter
what the brightness / contrast setting...?

Do you have a nice color picture that is for the most part accurate, and watchable...?

What company made the new flyback..... Do you remember OEM or Other....?


.

Timmy; Be aware that coils, and capacitors act on the signals coming through them so
to speak.... The raw DC off the damper is pulsed at 15K/cps. The voltage needs to be measured
at a point specified by the schematic. There is no way of knowing what is at the Damper
cathode, and no way of knowing what it's going to do to your test equipment....


Or if it's going to read it correctly....

My schematic is only that, I don't have a full service manual, and do not own a set like that,
or have recent experience on it.... SO be careful... Only use the HV probe.... ***

But There may be some validity in checking around there.... Because you say that you have
had retrace lines on the screen.... And I remember you saying something about how the
screen controls are set..... Do you always have retrace lines on the screen, no matter
what the brightness / contrast setting...?

Do you have a nice color picture that is for the most part accurate, and watchable...?

What company made the new flyback..... Do you remember OEM or Other....?


. well i will use the hv probe in that area to get an idea whats there. the flyback is a thordarson 273 and so was the one i took out. the color drives, rgb are fully counterclock, off and with them down like this i dont have the lines and i dont think its retrace but rather these color drives appear to be driven to hard by adjusting the right way in the setup mode maybe because of the lack of hv these drives need to be low to be even for the amout of hv present. set this way the picture is good but on white scenes its a different story or other scenes the colors will change alittle and or the pic will pull in alittle at one end. but is watchable. if i set the colors up the right way i have rgb lines across the screen and lots of blooming and brightness and contrast up or down makes no difference. right now with the drives down i have no lines and a decent picture but it is far from right and i dont want to leave it like this after spending so much time looking for this problem to just leave it alone now. the only thing i have to test a hv source like around the damper is the hv probe and i have been shocked many times, i dont like it but i try to be careful.

Don't worry about the shocks.... They're good for-ya- I got a good one once off some 17"
tube set I needed to adjust something and stuck my hand in there, and I watched a spark
jump from the picture tube to my hand on one side, and from the other side to the cabinet.
It cooked the skin and was a hard spot on both sides for months.... And dammit I'm still
here.... And stayed there for the rest of the day, and kept going back day after day...

Just remember to keep only one hand in there, and no path through you to ground....
So be careful what you wear, how you stand, and what you stand on...
No kneeling on cement floors...... Rubber mat maybe two if on cement.

It sure sounds like the picture tube does not have a proper bias setup... Overdrive
all the time.... Something is wrong there.... Have you gone over the voltages...?
At the picture tube pins...?

Lets check


Pin 3 I have 315V
pin 6 should be around 200V
pin 7 600V

What do you get....?

Anyone have good numbers for both sides of the pots on the screen controls...?

Anyone have ideas....? Worry about this now, or not....?

Added second picture with question Kine bias pot good...?

.

Don't worry about the shocks.... They're good for-ya- I got a good one once off some 17"
tube set I needed to adjust something and stuck my hand in there, and I watched a spark
jump from the picture tube to my hand on one side, and from the other side to the cabinet.
It cooked the skin and was a hard spot on both sides for months.... And dammit I'm still
here.... And stayed there for the rest of the day, and kept going back day after day...

Just remember to keep only one hand in there, and no path through you to ground....
So be careful what you wear, how you stand, and what you stand on...
No kneeling on cement floors...... Rubber mat maybe two if on cement.

It sure sounds like the picture tube does not have a proper bias setup... Overdrive
all the time.... Something is wrong there.... Have you gone over the voltages...?
At the picture tube pins...?

Lets check


Pin 3 I have 315V
pin 6 should be around 200V
pin 7 600V

What do you get....?

Anyone have good numbers for both sides of the pots on the screen controls...?

Anyone have ideas....? Worry about this now, or not....?
. ok solid colors-red-195v blue-186v green-193
white with colors-red-760v blue-757v green-759v
yelblue-280v yelgreen-276v yelred-245v this is the voltages when set up the right way but since lowering everything its less now. compared with the sams i have here the sams gives up to 680v to my 760v. i do believe i checked the kine pot as well but thats on my list again to check and the bias is counter also at this time.

I'm thinking your B+ Boost is too high.... It's showing up in the picture tube
bias circuit.... Problem is down around the coils and caps near efficiency coil,
all that goop around there... Resistors, caps, coils. Lets take a breather and let some
people with more time on this set chime in on what they have seen around
this area....

That sams have setup for the Horiz Efficiency coil.... Something we can use...?

.

I'm thinking your B+ Boost is too high.... It's showing up in the picture tube
bias circuit.... Problem is down around the coils and caps near efficiency coil,
all that goop around there... Resistors, caps, coils. Lets take a breather and let some
people with more time on this set chime in on what they have seen around
this area....

That sams have setup for the Horiz Efficiency coil.... Something we can use...?

. the sams i have says to use a 500ma meter a .47uf cap across meter a short across horiz oscill cathode coil pin 8 to ground ect adjust min current and not to exceed 210ma. it explains doing this and keeping track of hv current. so you think there could be a problem in the chroma board, hmmm i thought this may be a while ago but it remains to be seen.

No chroma board should only have color osc, demod's stuff like that, not B+ Boost
stuff on it....

If you feel that you can handle the efficiency coil adjustment I think you should at least
set up for it, and see if there is a working adjustment there.... Like some range, and
keeping under the current they recommend.....

Be very careful with the coils, you don't wanna do any damage with that stuff, It'll
be on the brittle side....

You may want to look at measuring the B+ Boost with that HV probe....
This has it marked, you can see it on the schematic near the 6BK4 tube.
They don't give a number. Sams might say something about B+ Boost,
check it out.... You can see how the B+ Boost goes right over to the pin 3's
of the screen adjust pots.... Your voltages look 100V too high, even at
cutoff.... I wonder what they would be if turned up a little.....

http://www.boxcarcabin.com/rca-ctc11-schematic.gif

If you can determine if the Boost is too high, then it's a matter of
testing each component to see if you can find it....

Is that focus rectifier good...? You said some resistor near the focus coil
was burnt up, was it R109 - 100K...?

Also you replaced the flyback with a Thordason same as was in it when you
got it, you have to begin thinking that two pins may be switched... You
may need to see how to check to be sure that that transformer was the
right way to begin with.....


.

No chroma board should only have color osc, demod's stuff like that, not B+ Boost
stuff on it....

If you feel that you can handle the efficiency coil adjustment I think you should at least
set up for it, and see if there is a working adjustment there.... Like some range, and
keeping under the current they recommend.....

Be very careful with the coils, you don't wanna do any damage with that stuff, It'll
be on the brittle side....

You may want to look at measuring the B+ Boost with that HV probe....
This has it marked, you can see it on the schematic near the 6BK4 tube.
They don't give a number. Sams might say something about B+ Boost,
check it out.... You can see how the B+ Boost goes right over to the pin 3's
of the screen adjust pots.... Your voltages look 100V too high, even at
cutoff.... I wonder what they would be if turned up a little.....

http://www.boxcarcabin.com/rca-ctc11-schematic.gif

If you can determine if the Boost is too high, then it's a matter of
testing each component to see if you can find it....

Is that focus rectifier good...? You said some resistor near the focus coil
was burnt up, was it R109 - 100K...?

Also you replaced the flyback with a Thordason same as was in it when you
got it, you have to begin thinking that two pins may be switched... You
may need to see how to check to be sure that that transformer was the
right way to begin with.....


.the resistor that is across 2 tabs on the focus coil its new and ok the original resistor was burned in 2 and dont know why but its been ok since the new one. the cathode current has a good swing as i can adjust it from around 180 all the way to over 210 ma . the focus rectifier is the 1v2 and is good along with any other resistors that go with it . i think there was a 1 meg and a low ohm resistor at the focus socket where its fed from the fly for the 1v2 heater. as for the fly being wired i went over the sams and the connections to make sure nothing else was wired wrong after finding the focus circuit wrong. if i turn the rgb drives up even al;ittle i get the lines and the blooming. i will have to get to that boost voltage to see what it is and if it is to high im not sure where to find the fault. what 2 pins are you saying may be switched ? i think the 1 meg is the focus wire to the crt.

the terminal guide for the focus coil looking in from the rear is this how to determine the 1234 terminals or is it the as if looking from the front in. the sams dont say and i could have the numbers backwards, if its the other way rather then looking in to the rear.

Each tie point on the fly has a clearly marked indicator as to what it is...?
Anyone have one of these on the bench and can put up a picture of it for
reference...? Does the Sams have resistance checks between each pin set
to check against a resistance number...?

Is there a way to check to be sure these three points are guarantied
wired correctly.....?

For coils:
They usually mark it on the schematic, for default I go to tube view, clockwise
looking from above and one pin is usually got an identifier, it's pin 1.
Resistance checks are a good backup for things that are not clear.
Even if you have to go and test another coil somewhere else in the set...

Thordason usually packs a install note with their transformers, and in some
cases Sam's notes replacement part oddities, like a tie point not internal
on a replacement fly.

Whatever you do, don't swap any wires until we have a really really reasonable
bit of evidence that something may be wrong with the way it's in there......
If this thing explodes I want it to be because we decided to dynamite it
on purpose from a safe distance and film it for youtube....

Anyone got picts of focus coil & flyback wiring we can check out as reference...?
Any replacement notes, etc. Ideas, dynamite, demo caps remote det. ???
.

ok i have the paper from the focus coil i got from moyers and the number 4 terminal has no connection and on the coil it has 3 wires tied together the only ones used are 1 2 3 the 4th one is just a tie point for the coils so i have that wired correctly.

well the terminal coming off the damper that says dont measure would be the hv end of that tube and the schematic shows the centering is tied to that damper terminal and my hv probe just bearly moves and if it were 1kv the needle would move half of the room to the 2kv mark but its not. i would have expected it to move enough to see.

The do not measure end of the damper tube (cathode) has HV AC pulses on it, and the HV probe will only measure DC....Unless it is an HV oscilloscope probe.

You will not get any meaningful readings from the damper cathode so don't bother measuring there...You are more likely to damage your equipment measuring that point then get meaningful data.

ok in the other post you asked about the crt pins 3- 6 - 7 you said 315 -200 - 600 i just check those and they are 3- 583v 6- 194v 7- 584v now i also checked pins 3 - 11- 7- all 3 of these came up 584v and this is with the drives counter if i raise the 3 drives they all are 760v . 584v seems to be alot with the drives completely down all the way. this test was with the crt plug off.

when i first got this set i spoke to a tv tech from way back in the 60s and is still repairing tvs and i told him about the hv and also the 3 color lines across the screen and that i could not get rid of them. well he was hell bent on telling me the crt was bad, no matter what he wanted to hear nothing else , the crt was bad period. how or why he was so sure and persistant that the crt was bad i dont know. i even told him it tested very good he tells me " it dont matter the crt is bad"

They should be with the crt plug on, but you did that measurement a few posts back...
I just thought it was high at what should be cutoff, just wondering out loud. Sorry.

.

I think the point BB on the flyback is the B+ Boost, this runs all the way up to
the picture tube screen adjustment pots through that resistor... R108 10K
Can you check that one, and be sure it's ok....?
Also can you verify that if the flyback has "BB" stamped on it, that there is a direct
connection to parts like C 113, and those 1.5 meg ohm resistors for the
shunt voltage reg. divider circuit...

.

I think the point BB on the flyback is the B+ Boost, this runs all the way up to
the picture tube screen adjustment pots through that resistor... R108 10K
Can you check that one, and be sure it's ok....?
Also can you verify that if the flyback has "BB" stamped on it, that there is a direct
connection to parts like C 113, and those 1.5 meg ohm resistors for the
shunt voltage reg. divider circuit...

.there is no BB on the flyback and there is no BB shown on my schematic.

if you are useing an rca schematic the locations are different numbers so the 10k that you speak of i think it comes right off the flyback on a 720v boost source and runs to the focus coil then to the linearity coil then to one of the 1.5 meg resistors at the hv regulator then to the yoke.

I'm confident the junction of R108 and C109 is the boost...It even says "B+ Boost" right above that next to the '6BK4' label... C109 clearly filters the boost line.

Ok, so lets get a number, and compare that to what someone else gets at the same
point and see what's going on......

.

ok i know where to get that from being this info is coming from an rca schematic and the sams i have is numbered different but thats ok ill use the hv probe there. my sams also shows 720v and 390v is this the 390 boosted up to 720v or is this 390v plus 720v ?

i dont know if it matters but if this boosted voltage feeds the RGB drives that i checked befor at min setting i can tell you that each one turned up max is 760 volts. testing numbers 3-11-7 pins on the crt socket unplugged is what i got.

I'm thinking it's 720V because of what is going on with the screen controls....
Just not sure of what exactly is needs to be... They are suppose to add to the
B+....

Now did you get a good reading on the focus voltage...? Your meter
doesn't load it too much....

.

the focus voltage in my sams states 4-4.5kv and all i get is just under 4kv but does go up alittle more after warming up and the pic is good.

from top to bottom the sams show the volts at the crt 290v
185v
620v
660
680v

should have a you tube dynamite party with this set the crt will be the best part of the show, lol, lol...:yes:

Just happen to have a CTC12 chassis sitting in the living room floor. Imagine that. Here are a few pictures of the flyback area. What chassis is the silvertone and which sams is it in so I can pull it and look. The screen controls usually have B+Boost on one end and B+ on the other. So the screen voltage will be somewhere between the two.

the chassis is a ctc12 clone 528.61115 and it looks just like these pics you have posted. the sams i have is set 655 folder 2 .

With you two guys and the same chassis sitting in front of you, I think there is something
in the L 105, L106 might be bad but the Eff. circuit is working so I'm not 100% on that
anymore.... But I still can't rule out an honest mistake in wiring the Horiz Output windings
that take off for the B+ Boost.... You guys should compare connection points and see
if something can be tracked down..... C 115 and C 116 were checked..or replaced....?

Bill if you would be so good as to post a few shots of those connection points from the fly
to the Boost supply, back to the damper, maybe Timmy can see something maybe was missed....

With most of the adjustment coils still doing something, and the set producing a watchable
picture, it's gotta be something small, overlooked....

.

With you two guys and the same chassis sitting in front of you, I think there is something
in the L 105, L106 might be bad but the Eff. circuit is working so I'm not 100% on that
anymore.... But I still can't rule out an honest mistake in wiring the Horiz Output windings
that take off for the B+ Boost.... You guys should compare connection points and see
if something can be tracked down..... C 115 and C 116 were checked..or replaced....?

Bill if you would be so good as to post a few shots of those connection points from the fly
to the Boost supply, back to the damper, maybe Timmy can see something maybe was missed....

With most of the adjustment coils still doing something, and the set producing a watchable
picture, it's gotta be something small, overlooked....

.the pics that were posted i was able to compare all what i did to his chassis and its all correct. both the c 115 and 116 were changed. L105 and 106 both come off the damper and they are not burned or discolored in any way and besides i think if one was open i would have a more obvious problem.

Shorted, or partially - you are right they would not be open....

Sorry Timmy, it's just that overall, the Boost seems to be the thing that could be
out of place, and there is not much to it..... I would even at this point check to be
sure the numbers are correct for the flyback transformer... I would almost be ready
to swap parts one by one from an identical set till I found the problem....

.

even though i didnt clip one end of L105 and 106 and checked ohms they looked ok as far as being discolored and they were not so i left them alone. the flyback is a thordarson fly 273 and it is correct. i think ill take the chassis out at this point and look again for anything. if i had to check boost voltages with the chassis out could i keep the anode wire away from everything should i have to test.

Well, I'm thinking like this.... Chokes, and Capacitors help shape signals, the Boost is
too high-we think, So that leaves some signal out of phase, spike too high, etc, to make
a voltage too high at the screen grid controls, and HV reg- that one we have measured,
and we also see the effects..... So- this all leaves a hand full of parts that could be at fault,
or somehow way off in value, possibly switched etc. before you got it, since it's had this
problem when you got it.... I know you been looking at it for years, but it still leaves
the problem intact, so we're missing something.... Gotta check everything, even if you
take today off, leave it and do it another day.... I know answering questions like
"are you sure the fly is the right one?" is stupid.... But I Can't think of much else....

At this point I would have to be looking at circuit errors before you began replacing parts
and the errors may still be there because no one thought there could have been a
part in the wrong spot when you started this project....

.

Well, I'm thinking like this.... Chokes, and Capacitors help shape signals, the Boost is
too high-we think, So that leaves some signal out of phase, spike too high, etc, to make
a voltage too high at the screen grid controls, and HV reg- that one we have measured,
and we also see the effects..... So- this all leaves a hand full of parts that could be at fault,
or somehow way off in value, possibly switched etc. before you got it, since it's had this
problem when you got it.... I know you been looking at it for years, but it still leaves
the problem intact, so we're missing something.... Gotta check everything, even if you
take today off, leave it and do it another day.... I know answering questions like
"are you sure the fly is the right one?" is stupid.... But I Can't think of much else....

At this point I would have to be looking at circuit errors before you began replacing parts
and the errors may still be there because no one thought there could have been a
part in the wrong spot when you started this project....

.ok so i guess when i pull the chassis i will use the sams and go over the fly section wiring including again what i did. and at one time when i found the focus wired wrong i did look around for possible mistakes both by me and maybe from others in the past but i didnt find anymore so at this point i dont really know where to start looking besides the flyback area and somewhat beyond that. i do believe to some degree that the hv reg is working but rather something is preventing it from working properly. so i will check the kine pot ohms again just in case i didnt check that and maybe i concentrated on the hv pot but i have alot to check now and until i find something concrtete the chassis will probably remain out of the set. i dont know if the horiz hold control being turned all the way at the time i got the set going and me tweeking the coil on the vert board to correct that range on the hold control would have anything down the line to do with any of this.

i wonder if its possible i may have messed up in the ps capacitors when i recapped it. where do you think if you would have an educated guess as to what cap and voltages i could have messed up on that may give the effects its doing now. i am really grabbing at straws now, lol lol..... i realize now that i never tried this set when i got it i just tore it apart and began recapping and when i was done that was it so i could still be a fault here if i made a mistake, and in a way i hope i did and im able to find it and correct it. and if i did make a mistake in recapping i will never live it down, lol,lol...

you could check the B+ and see if its in the 400v range, that would clear the power supply.

when you say you found the focus coil wired "wrong" how was that determined?

did it look orig to the set?

still not clear on why the reg would be pulling ANY current at 19kv if it is that is wrong, would point to a bias issue between the flyback and the B+.

you need to understand how it works, at 19kv the shunt tube should be fully biased off, if its not there is a problem. At some point. Since the boost voltage is used in the grid circuit of the shunt, I would look there. for some reason I think you have term 1 and 2 reversed on the fly. that or something with how the focus coil is connected.

oh and dont just swap the 1 and 2 to see if I am right, just triple check the schematic to see if you have it right.

Well Timmy, there are LOTS of threads here that begin "I recapped this "" and now it
doesn't "" " Mostly those problems are caused by mass replacement, A possible misplaced
lead, wrong part, misread code, improper part, wrong tolerances, multiply any or two of
these things times 15 caps, and a lot of problems....

That aside, you received the set with problems... They remain even after all this time,
If it was miswired, and you didn't know it, or think of it, then it's still there....

It's just gunna take time and a little extra thinking....

I do not think it's the screen pots, not there... Flyback - good possibility. Parts around
it and damper - focus - good possibility....

.

terminal 1 and 2 on the fly that goes to the focus coil i just looked and those 2 terminals are reversed . i made the huge mistake as i didnt even pay attention to those numbers instead i put the coil back the way the old one was. so now the mistake was done by who ever put the provious fly in not only wired the focus recifier wrong which i found and corrected but also had those 2 terminals reversed and i didnt pick up on that until now. omg, could this be the whole problem here ?????

i dont get something here, the fly shows 1 and 2 but the sams shows the 1 goes to terminal 2 and 2 goes to 1 so they are not reversed because terminal 1 dont go to 1.

try wiring it correctly and see, if you are sure of the correct way.

a clue was when you said "the focus coil was wired incorrectly" anytime you find yourself thinking that way and its factory orig, you need to re think it.
do you have the paper work that came with the fly? it should have the wiring diagram on it.

Just take your time and be sure..... Check over a good part or the entire set before putting it back....

.

try wiring it correctly and see, if you are sure of the correct way. the sams clearly shows the fly terminal 1 goes to terminal 2 on the focus coil and fly terminal 2 goes to focus terminal 1 so i thought i had it but another dead end because i cant wire it 1 to 1 and 2 to 2 because that would be wrong as it can be confusing with the numbers opposite like this.

you need to look at the wiring diagrams that came with the fly and with the coil.
Sams assumes factory replacement parts, Besides Sams can be wrong.

if you dont have the paperwork anymore you can at least ohm out the fly and confirm the order of the terminals starting at the horz out plate cap and working down.

you need to look at the wiring diagrams that came with the fly and with the coil.
Sams assumes factory replacement parts, Besides Sams can be wrong.

if you dont have the paperwork anymore you can at least ohm out the fly and confirm the order of the terminals starting at the horz out plate cap and working down.

What he means by this, is that if you place one ohm meter lead at the plate,
then each tap on the transformer going away from the plate, should add a few
ohms to the reading.... That way you can identify close taps, and farther away taps....
But everything on that winding needs to be disconnected - it needs to have
all but one lead and the plate out of the circuit.

.

well yes that would be somewhat of a last resort because if i changed the fly and had any different problems then yes i could check it that way but i have the same problem from the old fly and with the new fly. so the 2 terminals being reversed during manufacturing i would think its highly unlikely being the old fly was from what looked like the 80s or could have been earlier, i dont know. so if anything i could check ohms at the 2 wires that go to the focus coil i guess to rule it out but 2 flys, same problem, hmmm. the ohms on the focus coil are ok also. c1 and c2 are in the right position on the centering pot and the wires leading to and from the fly are where they should be . i just jumped to the conclusion that those 2 wires were reversed but they are not both by the sams i have and the rca schematic. back to square one.

just make sure the bottom winding is the boost.

btw, where does the blue wire from the yoke connect to?

the bottom winding is by itself from the flyback to the f coil is #1 and # 2 is from the fly also and goes to the f coil but this one has what i believe is the boost and its a red wire coming from under the chassis. if you look at the pics from befor that ctc12 chassis has the red wire also and in the same spot # 2 terminal. the blue wire from the yoke i would have to pull the chassis to follow it but i did some continuity checks and it is where it should be as far as that simple test which i know is not accurate. but i will be pulling the chassis. i check continuity between that blue wire and the 6bk4 and terminal #1 of the focus coil then moves on to terminal #2 of the fly. if im not mistaken the red wire on the fly terminal #2 comes from the damper but not certain until i pull it out.

yoke red lead goes to the center term of the horz pos pot.

yoke blue lead goes to the bottom of the fly windings.

PLEASE no other info just confirm that. More later after you confirm.

ok pulled the chassis out alittle to see under it . yes the red yoke i know goes to the centering pot, center leg. the blue yoke wire goes under the chassis to a tie strip which has one of the 1.5 meg resistors its tied to that and also 2 red wires red also tied to that terminal one comes up to the fly terminal #2 which goes to f coil # 1 and the other red runs up to attach to a cap and the one of the coils on the damper. this is confirmed.

and the other leg on the horiz centering pot is a brown wire going to the other coil on the damper. this is confirmed too. i am also comparing what i find to my sams and the rca schematic and its looking the same as i have here.

...

Next is you need to determine if that lug on the fly is the bottom of the winding, squirrel boy went over this a few post back. and if that is also where the boost voltage (and therefore shunt grid regulator supply) is connected.

ok pulled the chassis out alittle to see under it . yes the red yoke i know goes to the centering pot, center leg. the blue yoke wire goes under the chassis to a tie strip which has one of the 1.5 meg resistors its tied to that and also 2 red wires red also tied to that terminal one comes up to the fly terminal #2 which goes to f coil # 1 and the other red runs up to attach to a cap and the one of the coils on the damper. this is confirmed.

blue should go to focus coil(w/100k mounted to focus coil),1.5 meg (part of shunt reg circuit),10k(part of boost supply circuit),.12 cap,bottom winding of fly.

BOTTOM WINDING OF FLY NEEDS TO BE CONFIRMED

blue should go to focus coil(w/100k mounted to focus coil),1.5 meg (part of shunt reg circuit),10k(part of boost supply circuit),.12 cap,bottom winding of fly.

BOTTOM WINDING OF FLY NEEDS TO BE CONFIRMED

The other end of the .12 cap goes to a tap on the efficency coil. That all sounds correct.

If Boost is low it is because your HV is low. Since you had 30KV with the regulator cap off I would assume it is capable of producing the 24KV needed under load. Low HV could be caused by insufficent drive from the H out tube, or from excessive load on the HV section. For now the screen voltages on CRT pins 3 7 and 11 may be close. Looks like Boost is 750 to 800 volts. The B+ should be 395 volts. So the screen voltages should be between 400 and 800 volts. Look at the CRT cathode voltages. They should all be close to 300 volts. These are controlled by the kine bias and drive controls. Double check the kine bias pot, and the resistors on either side of the kine bias control. The video out tube and associated circuit can also cause retrace lines and blooming because it can cause the CRT to draw excessive beam current. I would verify the componants in the 12BY7 video output circuit. There are several high wattage resistors between the plate and the Kine bias control and you could have some leaky capacitors. Oh yeah, do check the video output tube.
In a normal gray scale setup you start with Kine bias all the way down and the drive controls all the way up. You adjust the screen controls for a barely visible line. If one color does not make a line you leave that screen control up and increase the kine bias to produce a barely visible line, then bring the other colors screen controls up to match. With a normal brightness Black and white picture on the screen adjust the drive controls to eliminate color shading. One of the drives will usually be at max and you reduce the other one to eliminate shading.
If the CRT current is high and it is loading the HV section the Regulator current will be low. Regulator current should be between 85 and 140 milliamps.
I am a little curious about the screen voltage not going below 584 volts. Maybe the CRT is conducting to hard due to improper bias on the cathodes. Hmmm.

Regulator current should be between 85 and 140 milliamps.


Don't you mean microamps (uA)? The regulator works by loading the HV so if it is drawing 140mA from a 25kV source then it would be pulling 3500W through the flyback which is impossible.

Should be able to run about 100 roundies with that.

the only blue wire on this flyback is soldered from one end of the 47meg and runs up to the vert board it shows this in both sams and the rca schematic. i think maybe the problem is different color wires were used for the clone and rca. looking at the coil of the fly the bottom lead #1 goes to the #2 of the f coil and the top lead #2 goes to #1 of the f coil and on the 100k resistor, also on that tap is a red wire and that goes under the chassis to the 1.5meg and on to the .12 cap. the other blue wire is from the yoke and that is in the correct place. weather top or bottom wire the numbers on the fly are right with the numbers on the f coil . at least what both rca and sams shows as to what number terminals go where from fly to f coil.

either way its all in the right place. the .12 cap i could not get a .12 so moyer gave me 2 different caps to make up this 12 , and i also had changed the .15 cap maybe these are bad. my problem is i dont want to switch a wire from one place to another by placing what appears to be boost on one terminal and putting it on another when both schematics show it is correct now. i just want to be sure as to the wires with colors for the crt cathodes because i will check this with the color drives at minimum .the last time i check if im right with the cathodes , the yellow wires, they ranged from 280v 276v 245v.

you need to know if the fly is wired properly. that means you need to determine if the blue lead of the yoke is connected to the bottom of the fly winding.

did you confirm the bottom of the fly yet?

[QUOTE=DaveWM;3124016]you need to know if the fly is wired properly. that means you need to determine if the blue lead of the yoke is connected to the bottom of the fly winding.

did you confirm the bottom of the fly yet?[/QUOTE ok what shows on the sams is that the blue wire from the yoke is at the bottom of the fly interconnected with a red under the chassis which comes up and is on terminal # 2 labeled on the fly so it is correct.

Timmy - Do you still have the flyback that you removed from this tv....?

.

nol i dont have it i sold it to someone and it was fine and worked ok.

Yes I mean microamps. Sorry bout that.

i did already check a few resistors around the 12by7 video output tube only to find they were ok. i also tried another good 12by7.

The other end of the .12 cap goes to a tap on the efficency coil. That all sounds correct.

If Boost is low it is because your HV is low. Since you had 30KV with the regulator cap off I would assume it is capable of producing the 24KV needed under load. Low HV could be caused by insufficent drive from the H out tube, or from excessive load on the HV section. For now the screen voltages on CRT pins 3 7 and 11 may be close. Looks like Boost is 750 to 800 volts. The B+ should be 395 volts. So the screen voltages should be between 400 and 800 volts. Look at the CRT cathode voltages. They should all be close to 300 volts. These are controlled by the kine bias and drive controls. Double check the kine bias pot, and the resistors on either side of the kine bias control. The video out tube and associated circuit can also cause retrace lines and blooming because it can cause the CRT to draw excessive beam current. I would verify the componants in the 12BY7 video output circuit. There are several high wattage resistors between the plate and the Kine bias control and you could have some leaky capacitors. Oh yeah, do check the video output tube.
In a normal gray scale setup you start with Kine bias all the way down and the drive controls all the way up. You adjust the screen controls for a barely visible line. If one color does not make a line you leave that screen control up and increase the kine bias to produce a barely visible line, then bring the other colors screen controls up to match. With a normal brightness Black and white picture on the screen adjust the drive controls to eliminate color shading. One of the drives will usually be at max and you reduce the other one to eliminate shading.
If the CRT current is high and it is loading the HV section the Regulator current will be low. Regulator current should be between 85 and 140 milliamps.
I am a little curious about the screen voltage not going below 584 volts. Maybe the CRT is conducting to hard due to improper bias on the cathodes. Hmmm.the way you outline how to do the grey scale is correct and it is also explained the same way in my sams here and doing it this way does not work because having to use the bias pot for a color to show and doing it by the book , this is when blooming and the rgb lines occur and its just a mess, and the hv drops even more if i set it up the right way.

ok here are voltages with the crt cap plug on bright up, y blue 220v y red 220v y green 237v
w blue 557v w red 557v w green 558v
blue 192 v red 194 v green 190 v
with the other drives , blue and green counterclock the voltages raise up alittle. seems as thought that 557-558v is high with the color pots at minimum. i had done this voltage test with the crt cap off befor but tried it this time with the cap on.

the voltage off the diodes in the PS is 401 volts and i pulled the hot and the damper and there is 410 volts at what looks like pins 2 and 8. and 281 volts at either the last or first pin. if this is any help. i really think its odd that there is never any voltage in the crt just after turning it off anode short to ground there is zero even just turning it off.

You don't seem to understand what I am saying

did you EVER confirm the bottom winding of the fly (please don't reference the sams again). I told you how to do this and squirrel boy expanded on it.

the blue wire from the yoke must be connected to the bottom winding of the fly.

You don't seem to understand what I am saying

did you EVER confirm the bottom winding of the fly (please don't reference the sams again). I told you how to do this and squirrel boy expanded on it.

the blue wire from the yoke must be connected to the bottom winding of the fly.what i seem to be misunderstanding is what you mean by the bottom winding of the fly, could you please tell me what tap to see on a schematic other then testing ohms for this bottom winding. the problem here is i follow the sams and this blue yoke wire appears to be in the right place and if we are not on the same page and i move this wire then i will have fireworks.

i have the miller paper from the focus coil and what it shows is correct for the way its wired and it shows what the taps are, fly , boost source, focus rect, and they are numbered and this is how it is now so with everything using numbers to identify where things go they are where they should be including the blue yoke wire, so maybe i am missing something here like this bottom winding if its the tie strap on the back of the fly where the focus coil get soldered to its numbered and it all checks out even in the rca diagram.

I think he means mean the electrical bottom rather than physical (just to try and be more clear).

I will try to make this as simple as possible.

1) disconnect the wires from the bottom two taps on the fly, I presume they are marked 1 and 2


2) use a ohm meter read the resistance from the horz out plate cap wire to one of the terminals, note the resistance.

3) without moving from the horz out plate cap wire read the next terminal that was disconnected, note the resistance.

I will tell you what next after you do this and report back.


For everyone else talking about CRT pin voltages, remember per Timmy with the CRT anode lead disconnected the MAX voltage he could get with the HV pot maxed out was 22kv (IIRC) this is with the shunt tube connected.

well if electrical bottom of the fly at the focus connections, nothing but that fly wire at the bottom is attached to the f coil and can be seen on the pic as well on page 8 the one above is attached to the blue wire down under the chassis. the same as i have here.

well if electrical bottom of the fly at the focus connections, nothing but that fly wire at the bottom is attached to the f coil and can be seen on the pic as well on page 8 the one above is attached to the blue wire down under the chassis. the same as i have here.

ok I official give up (again). good luck with it.

I will try to make this as simple as possible.

1) disconnect the wires from the bottom two taps on the fly, I presume they are marked 1 and 2


2) use a ohm meter read the resistance from the horz out plate cap wire to one of the terminals, note the resistance.

3) without moving from the horz out plate cap wire read the next terminal that was disconnected, note the resistance.

I will tell you what next after you do this and report back.


For everyone else talking about CRT pin voltages, remember per Timmy with the CRT anode lead disconnected the MAX voltage he could get with the HV pot maxed out was 22kv (IIRC) this is with the shunt tube connected.

ok will do that and then report back.

11.5 ohms top wire 10.5 ohms bottom wire both bare no connections on then tested with horiz cap as one test lead.

Hi! Sorry this question is pretty frustrating.

Timmy, I have never seen a flyback from this tv, From the pictures Bill put up
I'm thinking it comes with the tube socket, and a few of the delicate wires off
the transformer are already attached to something so they don't break.....
If so, then you have easily identified tie points.... But since we all can't see
the tv at your place, we need to be sure all the connections are correct.

One way to check is to look at the resistance of each pin on the transformer
and make the assumption that as you add wire to the device, resistance will
increase. To check that you begin with your ohm meter at a known point, and
then work away from that point and see if you get what you expect...

If you look at this transformer, point A and point B are the closest points but
the winding is the largest, so putting your meter across A+B you will get a
starting resistance.

Write that down A+B= ?

Then take the ohm meter lead from point B and put it on point C This will
be a new total: It ill be A+B+C= Your meter will be on point A and C for this total.

Write that number down A+B+C=?

Now this is the tricky part, the bottom of the transformer is D But the largest
resistance reading looks like it should be between A and F. Now to me
I think Winding D and F are a separate winding.

It looks like both bottom coils are center tapped, so since the both coils lower
than the center tap should be very short, and parallel to point Resistance
between point D and E should be very small..

Write down resistance D to E =?

Also resistance between C and F should be almost twice the resistance of D to E

Write down resistance C to F =?

This is one way to find the bottom of the transformer. We're trying to confirm that point D
has been connected where it belongs.... I would be ok if you had the old transformer
and we could measure the points off it, without dis connecting these points
to make resistance readings...... But since you don't, you might want to
make these checks....

But before you go, I want you to know I am still concerned with the lack of HV on
the tube after you power down the set.... To that point Have you ever checked to
be sure that the correct heater windings go to the right tubes of the 4 tubes right
there..... It may be possible that something wired wrong there would be a bleed
off the HV when the set powers off..... And I have also been trying to still look for a
good reason why the 1 meg ohm resistor feeding the focus voltage burnt in half.....

Good luck with checking this stuff. You are very persistant with this set.....

.

i dont know these resistances are very close and if i use what the sams says as a reference one is kind of high. hope im looking at it right one is 9.3 and the other 1.0 dont look like what i measured,hmmm

well I will try one last time since you answered the question.

the 11.5 is where the blue lead for the yoke should go it is the bottom of the fly. aka point D on SB's photo.

the 10.5 is point E in the photo.

well I will try one last time since you answered the question.

the 11.5 is where the blue lead for the yoke should go it is the bottom of the fly. aka point D on SB's photo.i think i need a drink but i dont drink ,lol,lol the 11.5 was the top and that is where the blue wire via connected under the chassis was and it looks like the same in bills photo, the top tab. so you are saying the lower ohms is where it should go, but it then changes the connection on the focus coil.

11.5 is the bottom of the fly ELECTRICLY REPEAT ELECTRICLY, ONE MORE TIME ELECTRICLY.

this is where the blue lead from the yoke should be connected. if it is then fine.

look at the schematic to you see the bottom of the fly, that is the ELECTRIC bottom of the fly. I dont know how to be more clear on this.

if you are saying you have it hooked up right, blue lead the the ELECTRIC bottom of the fly then I can offer no more insights other than making sure the focus coil is ELECTRICLY connected right. I am not sure if that could mess with the boost voltage enough to screw up the bias voltage to the shunt.

Hi! Sorry this question is pretty frustrating.

Timmy, I have never seen a flyback from this tv, From the pictures Bill put up
I'm thinking it comes with the tube socket, and a few of the delicate wires off
the transformer are already attached to something so they don't break.....
If so, then you have easily identified tie points.... But since we all can't see
the tv at your place, we need to be sure all the connections are correct.

One way to check is to look at the resistance of each pin on the transformer
and make the assumption that as you add wire to the device, resistance will
increase. To check that you begin with your ohm meter at a known point, and
then work away from that point and see if you get what you expect...

If you look at this transformer, point A and point B are the closest points but
the winding is the largest, so putting your meter across A+B you will get a
starting resistance.

Write that down A+B= ?

Then take the ohm meter lead from point B and put it on point C This will
be a new total: It ill be A+B+C= Your meter will be on point A and C for this total.

Write that number down A+B+C=?

Now this is the tricky part, the bottom of the transformer is D But the largest
resistance reading looks like it should be between A and F. Now to me
I think Winding D and F are a separate winding.

It looks like both bottom coils are center tapped, so since the both coils lower
than the center tap should be very short, and parallel to point Resistance
between point D and E should be very small..

Write down resistance D to E =?

Also resistance between C and F should be almost twice the resistance of D to E

Write down resistance C to F =?

This is one way to find the bottom of the transformer. We're trying to confirm that point D
has been connected where it belongs.... I would be ok if you had the old transformer
and we could measure the points off it, without dis connecting these points
to make resistance readings...... But since you don't, you might want to
make these checks....

But before you go, I want you to know I am still concerned with the lack of HV on
the tube after you power down the set.... To that point Have you ever checked to
be sure that the correct heater windings go to the right tubes of the 4 tubes right
there..... It may be possible that something wired wrong there would be a bleed
off the HV when the set powers off..... And I have also been trying to still look for a
good reason why the 1 meg ohm resistor feeding the focus voltage burnt in half.....

Good luck with checking this stuff. You are very persistant with this set.....

. the resistor that burned in half was the 100k across the f coil.

OH, ok, my mistake...

Timmy, you may have to just make a map with resistance readings like the diagram I posted....
From Bill's picture I can't see all the wires, Only people familiar with this set like you and others
not me know what this looks like....

.

11.5 is the bottom of the fly ELECTRICLY REPEAT ELECTRICLY, ONE MORE TIME ELECTRICLY.

this is where the blue lead from the yoke should be connected. if it is then fine.

look at the schematic to you see the bottom of the fly, that is the ELECTRIC bottom of the fly. I dont know how to be more clear on this.well i do understand what your saying but if i move this wire to the bottom then it is now on a tap of the focus coil that dont belong there it shows both in the sams and the rca diagram, so i am alittle apprehensive about moving this wire for fear of burning the f coil or something else. if bill was able to take another pic of the connections on his chassis of the f coil we will be able to see why and what im saying here. obviously you guys know a hell of alot more then me but thankfully there is schematics to try to make sure and this is what im afraid of doing . the only connections on the f coil are 1 2 3 4 is not used and wont have anything on it.

look, you have to connect the yoke blue lead (boost) to the 11.5 ohm lug. THEN you have to hook up the focus coil CORRECTLY.

If you are worried about burning things up, just put the meter in the cathode of the horz out and keep an eye on the current, if it starts to go north of 210 pull the plug. Good thing about tubes is they are not instant.

Quit looking at the numbers on the Sams, hook up the coils ELECTRICLY correct per the schematic on the focus coil the the ELECTRICLY correct fly terminals.

You should be very careful before committing to moving any wires....
You need to get more pictures of this either from Bill, someone else, check
the other tv you have, I got several schematics off the internet a lot of
the ctc 10, 11, 12, 13, 14, 15's look a lot alike in the flyback area.....

.

look, you have to connect the yoke blue lead (boost) to the 11.5 ohm lug. THEN you have to hook up the focus coil CORRECTLY.

If you are worried about burning things up, just put the meter in the cathode of the horz out and keep an eye on the current, if it starts to go north of 210 pull the plug. Good thing about tubes is they are not instant.

Quit looking at the numbers on the Sams, hook up the coils ELECTRICLY correct per the schematic on the focus coil the the ELECTRICLY correct fly terminals.this is what im tring to explain the f coil is connected correctly i have went over it so many times now the only thing different is moving the yoke blue to the bottom lug it then becomes wrong as far as the f coil goes, the f coil is numbered and the boost does not show it as on that terminal both from the miller paper as well as the 2 schematics.

You should be very careful before committing to moving any wires....
You need to get more pictures of this either from Bill, someone else, check
the other tv you have, I got several schematics off the internet a lot of
the ctc 10, 11, 12, 13, 14, 15's look a lot alike in the flyback area.....

. the other tvs i have is a ctc15 clone without the tube for a rectfier and the other is a ctc16 clone.

It is NOT connected correctly IF you reversed the fly lugs. the two ELECTRICLY speaking bottom lugs connect to the focus coil (D and E on SB's photo).

You just have to figure out which lug is which between the schematic and the coil and connect it right ELECTRICLY.

so if i am going to put the boost to the 11.5 well then it was correct all along except it was not the bottom, on this fly its the one above that checks 11.5 not the bottom.lol,lol........

It is NOT connected correctly IF you reversed the fly lugs. the two ELECTRICLY speaking bottom lugs connect to the focus coil (D and E on SB's photo).

You just have to figure out which lug is which between the schematic and the coil and connect it right ELECTRICLY. i did this already but being this boost is said to be on the bottom goes against what im reading. so if i took the 2 from the fly and reversed them then that would be moving the boost wire to another internal tap of the fly and would leave the terminal in question on the f coil alone, right? it would then be using the 11.5 ohms.

look timmy, the schematic says the blue yoke lead (boost)goes the the lead that is the most distant from the horz out lead correct? yes or no?

Now if that is yes and you get 10.5 on one lug and 11.5 on the other RELATIVE to the horz out lead, which do you think is the most distant? the 10.5 or the 11.5?

just answer that, then I will respond with the next in the logical sequence.

I just want to make sure the fly is hooked up right.

Well if your ohm meter has the resolution...

A to D should be higher ohms than A to E

that is one way of identifying point E It has the higher resistance when measured
from point A. See the center tap Point E It's closer to A.

.

Dave what are you thinking about A to F ??
Would that be the farthest from point A ???

If it's just between D and E then forget it.

.

B to D = 11.5 per timmy I think, if so D is the boost/yoke/shunt reg
B to E = 10.5 per timmy I think, if so E is the one that goes to the focus lug 2

look timmy, the schematic says the blue yoke lead (boost)goes the the lead that is the most distant from the horz out lead correct? yes or no?

Now if that is yes and you get 10.5 on one lug and 11.5 on the other RELATIVE to the horz out lead, which do you think is the most distant? the 10.5 or the 11.5?

just answer that, then I will respond with the next in the logical sequence.

I just want to make sure the fly is hooked up right. 11.5 would be farther

ok so that is the one that is the boost/yoke/shunt etc..

now the other one the 10.5 is the one that goes the the electric lug 2 of the focus coil, do you agree that it is the next one up (ELECTRICLY) from the boost per the schematic?

do you follow this, does what I say make sence when you look at the schematic now? disregarding the number or physical location of the lower two lugs on the fly?

yes i agree that one measured 10.5 next up higher little less ohms and yes lug 2 of the f coil.

Hey !

You other 15 people watchin' ! Yah you !

We doin the right thing here ! ! ???

Any of ya got pictures of these connections yer willing to put up....?
.

:smoke::smoke::smoke:

ok so you have the blue lead from the yoke and the #1 of the focus coil to the 11.5 fly lug

the 10.5 fly lug is connected to the #2 of the focus coil. Nothing else is on the 10.5 fly lug correct?

is that correct?

hey squirrel boy what part of orange county are from?

ok so you have the blue lead from the yoke and the #1 of the focus coil to the 11.5 fly lug

the 10.5 fly lug is connected to the #2 of the focus coil. Nothing else is on the 10.5 fly lug correct?

is that correct?#2 f coil was on the lug that tested 11.5 ohms nothing else on that one

Pine Bush / Montgomery.
2 minor specs on the map..

.

Pine Bush / Montgomery.
2 minor specs on the map..

.oh ok my son goes to school in pinebush. i am there in pinebush 4 times a week.

I'm sorry.......... You should get him out before any real damage is done....

.

#2 f coil was on the lug that tested 11.5 ohms nothing else on that one

ok that was wrong. Do you now understand what to do?

per the schematic with the now correct understanding of which is the correct lugs of the fly?

yes i think so here goes, the lead that is supposed to be the boost and the blue wire from the yoke i have to put it on the other leg that measures 11.5 and then wire the f coil the right way, which would be just reversing 2 connections on the f coil, am i correct ?

I'm sorry.......... You should get him out before any real damage is done....

.well hes only in 2nd grade ,lol,

you have to look at it, I am not there so I do not know, just wire it according to the schematic now that you know the correct lug PER the schmatic. But I would guess yes you need to reverse the focus 1 and 2 since you orig had the fly wired backwards.

:Dwell i have to take a break i need to bring my son to his mom in PINEBUSH.......

you have to look at it, I am not there so I do not know, just wire it according to the schematic now that you know the correct lug PER the schmatic. But I would guess yes you need to reverse the focus 1 and 2 since you orig had the fly wired backwards. so you still suggest using the 11.5 for the blue wire thing? what was wired wrong was the heater connections on the 1v2 originally when i found that mix up in the focus circuit

11.5 goes to boost/yoke and lug 1 of F coil

10.5 goes to lug 2 only of F coil

~~~ I guess were going to have a bit of an intermission now ~~~~

.

I got the pop corn out.


Timmy are you sure you have the lugs identified correctly on the focus coil?
there should have been a paper with instructions on it. generally the 1st lug clockwise of the red dot is 1, then continue clockwise for the rest.

there is generally a ref dot of paint to make sure you have it oriented correctly.

then you still should use the paper instructions, they tell which goes to boost, which goes to the 130 pf cap etc...

when you feel like you have it all correct do the following:

Before power up
get the HV prob setup and in place.
have the horz out cathode meter in place to read the current
have the diddle stick in the eff coil ready to adjust
reset the HV pot to mid range.
check for any loose wires or solder blobs
check the wiring again.
have a B+ meter on the B+ 400v test point on the chroma board.

make sure all the cap leads (horz out, shunt tube) are in place
make sure the convergence board is plugged in
make sure the CRT anode is attached and will not fall out from the HV prob.

all tubes in sockets, CRT socket attached, kids/pets all accounted for...

power on:
check B+ should come right up to 400+ maybe spike higher until tubes warm up.
watch the horz out cathode current, should rise to about 200ma, if it goes over 210ma unplug set.
watch for smoke
hopefully you will hear the crackle of the HV and you will be able to set it up correctly with the HV pot now.

well let me just say that the blue wire boost is to go on the 11.5 lug, and #1 on the f coil ok , but this is where it was, it was on the 11.5 lug all along its just that it was not the bottom wire so i really cant move anything because i can move the wire to the bottom lug but that was the 10.5 on the #2 f coil lug. you said it was to go to the lug with the higher ohms and this is what i had explained i think on 2 pages back. and yes i know i was going to take all those precautions. the f coil is numbers 1234 and the miller paper shows it but my coil here has no mark except the mount key so i use the #4 to identify the proper sequence in numbers along with the sams , shows the shape of the lugs on the coil and #4 lug.i am not ignorant but i really am confused.

11.5 goes to boost/yoke and lug 1 of F coil

10.5 goes to lug 2 only of F coil

this is whats blowing me away because this is the arrangement it was befor

well let me just say that the blue wire boost is to go on the 11.5 lug, and #1 on the f coil ok , but this is where it was, it was on the 11.5 lug all along its just that it was not the bottom wire so i really cant move anything because i can move the wire to the bottom lug but that was the 10.5 on the #2 f coil lug. you said it was to go to the lug with the higher ohms and this is what i had explained i think on 2 pages back. and yes i know i was going to take all those precautions. the f coil is numbers 1234 and the miller paper shows it but my coil here has no mark except the mount key so i use the #4 to identify the proper sequence in numbers along with the sams , shows the shape of the lugs on the coil and #4 lug.i am not ignorant but i really am confused.

#2 f coil was on the lug that tested 11.5 ohms nothing else on that one

so which is it?

ok dave i have to run out yet again so i am going to confirm any of my mistakes and i will get back to you tomorrow. i see your quote from me so i am going to test the lugs again and get it right this time as we really got far ahead of things and i guess it messed me up,lol,lol. ill send you a PM with the number.

Timmy and I have been in contact over the phone.
I believe he has the flyback hooked up right.
A test was done with a known good 6BK4 as follows:

bad set 6BK4 installed in known working set, Known working set exhibits the same problems so the 6BK4 is causing the problem

Known good 6BK4 is installed in Bad set, 6BK4 quickly appears to short out around the filament leads. Tube is tested by retrying in known working set, confirmed prior good tube is toast.

So we concluded the regulator tube is the issue AND the bad set seems to be creating bad tubes from good tubes.

http://scottbecker.net/tube/sheets/137/6/6BK4.pdf

Timmy is going to check the HK voltage potential to see if it is exceeding 225v per the data sheet. I am thinking a problem with the voltage divider resistors (180k/150k) off the B+ that is used to float the shunt heater upwards to prevent insulation breakdown around the heater.

Timmy will 1st check the known working set pins 1 and 2 of the 6bk4 socket (HK) voltage and then compare to the bad set. I advised him to simply disable the HV for now by pulling the horz out while testing. remove the 6bk4 and read the voltages right a the socket.

I would also like Timmy to check voltage pin 1 to ground (shunt cathode) and pin 2 to ground (shunt filament). again the difference in the two voltages should be less than 225vdc




If there is a problem, I would guess the 180k side of the voltage divider (filament to B+) may have opened up or drifted up dropping the DC voltage on the filament.

Very good thinking..... But with 400V on the cathode I believe he said was there,
or it was on the grid, I bet it's the second resistor, R124 150K to ground... open
really pushing the potential up.... Yah I downloaded that tube spec sheet trying to see
what it's operating parameters are, and any notes on breakdown.... Didn't get lucky...
Good work, be happy to see this thread finished and locked forever....

Hope you get good news from him soon ! !

So how long does it take for that tv to kill one of those reg. tubes....?

.

the K is about +400v so if the heater drops to less than 175v he will have trouble. If
the bottom of the divider opens, the heater would go to +400v, 0 difference vs max of 225.

I guess it could go slightly positive (10-15v) with respect to the cathode ("not recommended to go positive" per data sheet) since the voltage divider begins right at the 405v supply (before the choke and vert out trans where the K voltage comes from, which puts it about 15v lower IIRC)

but anyway its something to check that has not been check yet, so fingers crossed!

Ahh. So you think the source resistor is opening, taking away that reduced potential
needed to prevent heater cathode breakdown.... And once that happens you
think that is not effecting the cathode voltage ??? in a downward direction from
whatever short develops Heater to Cathode.... Interesting....

Oh-Ya My fingers are crossed.... Poor guy a couple-a years chasing this problem....
I wonder how many times this cropped up in the field.... and how long it took
other people to find it....

.

it happened very quickly while he was try to adjust HV. Must have been just seconds into the process.

Timmy can you recall how long?

Ahh. So you think the source resistor is opening, taking away that reduced potential
needed to prevent heater cathode breakdown.... And once that happens you
think that is not effecting the cathode voltage ??? in a downward direction from
whatever short develops Heater to Cathode.... Interesting....


.

That's my thinking its such a simple circuit and reg stuff all checks out.
IF it turns out to be the problem you can bet I will be checking those two resistors out regularly, darn 6BK4's are not cheap.

My thinking is this

New tube goes in, gets smoked enough to drop the K down due to leakage just enough to screw up bias, Thinks tube must be good since it brand new, etc...


I had Timmy pull the back off a known good set to observe the look of a functioning tube (how the filament changes intensity as it regulates). I warned him of the X ray exposure so not to do this long just see how it should look when working. Needless the say the bad set tube did not behave the way the good tube set worked.

How would a leaky cap of pin 7 of the regulator tube affect it's operation? Just curious.

That should bring down the dc component as well.... But he said all those caps
were replaced....

.

SB is right, that was discussed as well.

all the usual suspects were check or replaced some more than once.

the two 1.5 meg resistors check and replaced
the .0033 grid to K disc cap, replaced SEVERAL times
the HV pot checked for operation
The .1 Filament to chassis, replaced.

when he said he saw sparking around the heater that is what got me thinking to check heater potential. Voltage checks should give us the answer.

I sure hope this is it as I am out of ideas.

Sounds like you nailed it !
I don't remember anything about sparking....
Fingers still crossed.....

.

Sounds like you nailed it !
I don't remember anything about sparking....
Fingers still crossed.....

.

That came up in conversation, after I told him to try a working tube from another set. He has the cover off so it can be seen, which may have gone unnoticed before if it was just installed with the cover in place. This is why long distance diagnosis is so hard. Its nearly impossible to cover all the bases. But to his credit he did note it and report back, with out that little nugget I would not have thought to check it. The knowledge of how a working regulator tube looks is kinda hard to describe, which is why I wanted him to look at one in a good set. So while powering up the bad set he was looking for the correct operation.
I just really really hope this turns out to be the problem.

That should bring down the dc component as well.... But he said all those caps
were replaced....

.

I knew it had been replaced, I was just thinking what it's function was. I assumed it was a ground path for the ac pulses on the tube.

:scratch2:ok the .12 cap that i replaced was in question as to what values i put together to make the .12 , so here it is .1- 630v and a .022- 630v in paralle. ok now on to the voltages, pin 1- 6bk4 to ground 407 v maybe the grid here was up a bit at the outlet, pin 2- to ground 94 v . pins 1&2 - 315 volts and pins 1&7 - 315 volts at first start up this 315 was 330 volts but then dropped. each filiment wire to ground was 94 volts so after checking these voltages i did not go into the other set to compare because if this voltage is to be under 225 volts then clearly those resistors must be a problem and i will have to check them. the 180k and 150k thats next....:smoke:

Yah, doing the math, should be around 180v give or take tolerances....

.

I just pulled the back of mine, 177v pin 2 to ground about -210 pin 2 to pin 1.

I am posting up a very short video, should be there soon. I will leave the set out in case Timmy gets the HV working and has focus issues, I can look at how I have mine setup.

my video ran out before I could get the pin 2 to ground but I do show the 2 to 1 DC voltages.

https://www.youtube.com/watch?v=ALleVRf3gBE&feature=youtu.be

here you go timmy

well i got a problem here the 150 k and the 180 k i had already put resistors in series awhile ago and the 150 tests at 156k and the 180k tests at 182k so im looking for maybe a mistake on the 400v source or the 390v source maybe i crossed one of those sources. i just cant believe this crazyness. i need a smoke first.

if the resistors check out you will need to go back to where they connect up.

the 180k goes to B+400v check there with meter, then check where the 150k goes to ground should be 0v there, then check the junction, should be +180v there. has to be.

if you replaced the resistors you need to make sure you connected up to the correct location, esp the B+ side. During our talk IIRC you said it was connected to the output of the 1s diode of the doubler, that is NOT where the 400v is but more like where the 200v is. the 180k goes to where the 400v is.

if you have it hooked up right (180k to 400v) and the junction is still around 90v, it would mean you have a leak to ground somewhere, disconnect the wire at that junction and check the voltage at the junction of the two resistors again, if it pops up to 180v from the 90v then..

perhaps that .1+.022 cap. if this is the case try disconnecting the .1+.022 cap (lift the ground side) and check the voltage again.

ok i changed the resistors here and one end 180k starts at the diode and confirmed 400v , then goes to a tie strap and then the 150k from the tie to ground its all in the right place.

what junction, the filiments to ground ? so at this point it could be any cap from a positve source to ground causing the filiment voltage to be hi or am i off here.

disconnect the wire that connects to the junction and so all you have is the two resistors in series, then read the voltage at the junction.

more from Timmy

with the voltage divider in place but not attached to the filament he get 180v
attaching the filament drops it to 90v, not right.

the filament string reads infinite with a ohm meter (disconnected from the voltage divider) yet when connected drops the voltage.

I advised Timmy to disconnect the .1 cap, as its the only thing that is connected to ground and the filament. The cap replaced but could be the issue if it leaks when voltage is applied. I assume Timmy used a 630v cap for the replacement. FYI I always check new caps going in for value AND leakage at rated voltage.

Timmy understands that the voltage at the 180k/150k should be 180vdc and SHOULD NOT DROP when the filament wiring is attached. All the test where conducted with the shunt tube out of the socket.

Timmy please confirm the above esp the test were conducted with the shunt tube out of the socket (and I hope the horz out tube out also, so you dont have to worry about HV being produced).

more updates

further looks at the schematic shows the same filament supply goes to other tubes with elevated cathodes, the CRT and the second IF tube.

thinking maybe a HK short, the CRT is not connected, so he pulled the 2nd IF still dropping the 180v to 90v.

.1 cap off shunt to ground, disconnected no help.

Timmy will trace all wires, disconnect one at a time until 180v is restored and the dropping point is isolated. I did see a couple dog bone caps on the IF strip, grounding that 2nd IF tube filament. So maybe disconnecting the IF H1/H2 (2nd IF heater)supply may be a easy place to start.


Realizing the CRT is at risk (of a HK short) , I think I will routinely check the DC potential of all my set, just in case of some drifting of that voltage divider.

C 309 and C 310 up there filaments to ground at the IF tube also.....

Yah, don't pass on the thought that it could be an internal tube short... I chased one
of those once, refused to believe a tube could do that... Also crud or a wire or something
actually on any of the tube pins, or socket, top or bottom.... Maybe that set is haunted... Cursed....


-WOW- This problem is a real Hum-Dinger !

.

Timmy
c309 and c310 are the sams c25 and c26 those are the two dog bones we discussed.

SB is using the RCA numbers from the rca schematic.

PROGRESS!!
c26 (C310) burned to a crisp, a likely source of leakage due to carbonization.

he is going to replace and hook all back up, retest pin 1 and 2 of shunt to see if down below max of 225 (was 310).

if that is the case then should be safe to try a good shunt without fear of HK breakdown.

Question.....
When Timmy Makes the reading off the resistors and gets the 180V, is the filament
winding from the transformer still connected....? He is just removing the tube
feeds right...? And it's good DC that you are reading....

How about the old "tin Wisker" trick on any of the tubes that are on PC boards...?
Burnt looking PC board material near those smaller tubes....

AH ! I see you slipped a post right under me ! !

Good deal ! ! ! Fire that baby up ! !

.

Very interesting problem indeed. I will definately use this information when I do get around to restoring my 12. My parts chassis has no B+. I have never powered up the one in the set since I need a CRT for that one. I may just repair the parts chassis so that when I find a tube I can just swap chassis. I can connect it to my test jig for serviceing.

ok here is where we are, just got off phone with Timmy..

HV is holding at about 23-25kv with scene changes. I think it should be better but at least its not down to 19kv.

Max HV with brightness down is about 28kv min is about 22kv.

gray scale procedure does not seem to work, that is service switch to setup, bias at min and try to get all three to just make a line.

Gray scale was eventually set by eyeballing a raster for overall grey/white tint.
did not get too into setting low lights and high lights with screen pots and drive pots.

interesting thing was with just a raster the kv held right at 25kv while adjusting the brightness pot from full dark to full bright, so the regulator took care of that, but seemed to jump around with reg programming.

I am tired, don't know how Timmy can hang with it but I did make a couple things to check

swap the shunt tube from one set to the other (the shunt he was using was from yet another set). He has two silvertones so I suggested comparing the shunt performance side by side.

check the bias pot (it seemed hypercritical, just moving off min would bloom and kill all HV) wanted him to use an analog to judge how smooth it is, only has digital, is suggested at least to confirm the resistive element had not opened at the far side (and the wiper was making the element complete in one sweet spot only).

check the Sam L14 transformer for continuity 7 ohms one side 12 the other.

The setup (using the switch) acted very odd while he was doing it on the phone. Did not work right at all. This bothers me.

On those control pots, I don't have one of those sets, but he has had this problem for
years, and probably played with those controls much more than they were ever meant
to be used in their life... They could be really in need of cleaning, or if they are PC board
based the solder connections to the board could be faulty...

Also that cap you guys just replaced was not subject to that much of a high voltage
while it was working.... 200V ~ There may be other caps same manufacturer that can
be getting ready to go.... Blanking, or Video Amps.... Coupling caps....

Does the set tend to blank-dark, or go white and cut the HV that way....?
I guess it would be a good thing to also check to be sure all that other stuff
around the flyback is all connected, nothing left unsoldered...

If you leave it alone for 20 minutes with a show on, does it do it on it's own
and can you point to specific types of things that cause it...?

Did you replace that 6GM6 that also had the DC added to the filament ??
Might be a good thing to do, just temp swap it with his other set....

.

I did not see the CRT so cant say for sure if its blooming and killing it or biasing off killing it but since the HV is dropping I have to assume its blooming too much current. I just want to make sure its not opening on the hot side as soon as the wiper moves, going to ground potential, resulting in a full on bias of the CRT.

with the HV somewhat working I would recommend looking into getting the CRT bias checked. a couple meters on the G1 and K should show whats going on. again I prefer analog as its just easier to see. is the K all over the place with the adjustment of the bias pot? this what I think but it would be good to confirm the G1 is holding steady.

Since he had two of the same chassis (silver tone RCA clones) on thing he could try is to monitor the K/G1 voltages off both when switching from normal to service and then see what happens when adjusting the bias and drive pots.

Also see how responsive the G2s are compared to a working chassis. again I really think a good analog meter is much better for this.

ok L14 measures 11.6 and 6.6 ohms so thats ok. the crt bias measures 6.20 k from terminal end to end and the wiper, the ohms are smooth. what is an acceptable ohms for the bias pot at full counter. all resistors around the service switch test perfect. i even took the pot apart to see if any burn marks or anything that dont look right, it looked new. i am curious as to which wire and where it goes is the actual one that triggers or determines the hv regulation because if the regulator is good now then if there is anything else further up the line in the circuit somewhere that maybe off a bit because this is the biggest improvement in this set since i have it. so its just about there. 6gm6 i changed even though it tests good just the heater lit very fast as opposed to another new one i have so i changed it to avoid anything later with that tube if the heater was stressed in any way.

Well, if he's into it, you could pick a few on ebay and send him a link to a couple
of acceptable quality meters and he can just get one or two...... There were a few
smaller Tripletts that are on there all the time, and are good to have around when you
"need analog" like this case... And they won't break the bank... Under appreciated meters...

.

pot and L14 sound good.

I suggest since it seems hyper sensitive to blooming you try the following.

start with just the raster, setup for the good 25kv from low to full brightness.

connect a meter to the crt red cathode lead (yellow/red) note voltage and adj crt bias, see what happens It should smoothly decrease in voltage as you turn clockwise.

do the same for the other cathode leads yellow blue and then yellow green, but not only test the bias pot but the two drive pots as well on those colors (green and blue, there is no red drive pot).

see if all the controls result in smooth gradual voltage changes.

just checked the hv pot its .513 meg full counter and 110 ohms at max, does this sound ok ?

yep that is correct.

you can still get a solid 25kv on the raster from full bright to full dark right?

if so you need to focus on that crt setup. starting with the checks of voltages at the yellow stripped leads as detailed above. The setup does not seem to be working, need to find out why is so touchy.

So lets say you put on the Honeymooners, there is a nice steady watchable picture...?
And this blooming that happens, it's during regular programing ?? And if it is -
when you leave the G's Screens, and Kine Bias alone, and turn the front of the set
brightness, and contrast back and forth slowly it seems to work ok.... or not...?

And if you turn to a raster only spot no snow between stations between detentes,
you have a blank screen and if you leave it, the screen is steady...?

And in that spot, adjusting only screens, or bias, causes the blooming...? Are the drives
not effected.... They don't cause any blooming....?

.

i just looked at the crt ground where the chassis makes contact with the foil strap and its black on the chassis like coal dust as if its not making good contact and some wipes off.

yr 200v hi low 232v yg hi217 low267 yb low 216 hi 266 v bias pot up and down bright screen

all 3 of those yellow with stripe should be closer to 300v (crt cathodes)

all 3 of the solid color RGB wires should be closer to 200v (crt control grids)

all 3 of the white with stripe should be around 600's (crt screen grids)


the yellow strip gets it voltage from the plate of the 12by7 should b about 300v pin 7

with the raster set to normal full brightness check those yellow striped wires again.

yellow wires red 250 green 255 blue 258 v
white wires red 730 green 622 blue 750 v
solid wires res 192 green191 blue193 v

these voltages are from setting it up for best picture and b&w screen. i can set them by voltage readings from sams but it wont be right. and the hv is at times low and does alittle dipping.

looking down on 12by7 going counter if thats 7 its 145 volts

yellow wires red 250 green 255 blue 258 v


and that is with the kine bias fully CCW? no wonder it blooms instantly
and turning the kine bias CW just reduces those even more?

You did say this CRT tested fine for emissions and cut off right?

and that is with the kine bias fully CCW? no wonder it blooms instantly
and turning the kine bias CW just reduces those even more?

You did say this CRT tested fine for emissions and cut off right?

the crt cutoff was close for the red but better on the other, and the bias is ccw. otherwise emissions good