ok im back again with the same set it is a 63 silvertone ctc12 clone. i have a few issues and to this day i cant seem to solve. on the schematic there is a section of the 6bk4 and it has 2 lines coming together with a circle on each end and this is where to check regulator current but it shows a jumper that goes across it so is this jumper always across these 2 lines and then removed to put a meter in between and then put back or is it left separated. because i removed this jumper and now have no control of the hv 30kv is high, not right. the other problem is like on modern tvs there is a screen control on the flyback and if adjusted to high then there is lines across the screen until its lowered and this is what i have on this silvertone it as though the bias is to high but it is counterclockwise all the way down and these lines are each one is red, green, blue, and no mater what i do adjusting, subbing tubes nothing gets rid of them i am thinking there may be a resistor or a shorted cap in the chroma board , i just dont know at this point. i have since replaced the flyback when i discovered the 1v2 was wired wrong and i had focus issues now i dont just the lines. so i dont know if its a bias issue or a color drive issue. hopefully someone can shed some light on this never ending sega with this set. so what ever is going on here still is affecting the hv if that jumper stays in place when not checking reg current then ok but i then have to have the hv at max to get decent hv and if something is being driven to hard will have an affect on the hv and this is what it seems like thats going on here. the 1.5meg resistors are good and the high watt resistors around the drives as well check good. :scratch2:

You need to replace the jumper, its only removed for testing with a current meter.

The diag lines you see I suspect are due to trying to drive the CRT too brightly.

You need to follow this order

1) set the HV up with a HV meter on the CRT anode and the current meter for checking shunt current on the 6bk4, follow the sams procedure, please don't jump around. This wil include not only the shunt current but the cathode current of the horz out tube, again all of this is in the Sams.

2) setup up the drives using the setup switch and again following the procedure, this will include the correct setting of the bias pot or switch (which ever is used).

3) check the grey scale and adjust the bias pots for no tint in the high lights again part of the setup covered.

My "guess" is you are simply driving the CRT too hard (maybe its getting soft).

If for some reason the 1st 3 steps do not work then you may have a circuit problem that should be addressed. Good HV regulation is a must, trying to get a good pic with out it is a waste of time. You also need a good grey scale setup, if the set can not produce a good BW pic then no need to try for a color until that is resolved.

ok well i have done this except the reg current on the 6bk4 and the bias IS DOWN ALL THE WAY AND THE 3 COLORS RED, GREEN, BLUE drives are completely down, off and still have lots of color and with the b@w pic there is still visible lines but bearly. how else could i be trying to drive the crt to bright i took away all that brightens the crt and still have the lines. this problem has gotten worse each time i would run it for alittle while and now its at the point im trying to get to the bottom of it,lol, its making me crazy. this gave me the idea that something on the chroma board may be bad, i have done so many grey scale setups. the reg current is in milli amp or micro amp or is this the same,lol...

with the G2 drives all the way down and the bias all the way down you should not be able to get the setup lines and the crt should be dark.

You have a problem with the voltages going to the CRT pins. You need to get out the VTVM and start checking the K, G1 and G2, to narrow it down to what is the problem, then you need to see if the pots that control them are indeed working.
but 1st you need to make sure the HV is correct.

If you do not already own it I HIGHLY suggest you get the TAB book vol 1 RCA service manual by Carl Babcoke. He does a great job explaining all aspects of early RCA color sets, and goes into great detail regarding trouble shooting.

yes the crt is dark but still see the drive lines and i already checked the pots and they are in range. when i put the jumper back i will be able to adjust the hv but what is going on it struggles to regulate yet i can get it adjusted to 25kv but with the hv pot maxed. so ill have to check the voltages at the crt and hopefully ill get somewhere there.

Could your control pots be going open, or the supplies driving them be feeding the wrong voltages?

EDIT: Should have refreshed the page before replying.

problem is i dont have any books of sort to give me any guidelines as to what voltages should be at a given place or anything to compare. so im working in the dark,lol,lol.....

you must have the jumper in that's a given.

You should have good HV regulation. If not then you need do the HV setup which includes current checks of the 6bk4 and the 6JE6.

the next step on what to check will be dependent on the outcome of those checks. Stop worrying about the lines until the HV is working correctly.

I am not going to list the possible problems as its just a lot of speculation with out knowing the current in the regulation and horz out tubes. I don't believe in random attempts to solve a problem. there is a methodically approach diagnostics. You MUST have good HV regulation, after that you can move on to the next issue.

problem is i dont have any books of sort to give me any guidelines as to what voltages should be at a given place or anything to compare. so im working in the dark,lol,lol.....


the book I referenced is on ebay all the time.

The Sam's should list voltages at important points on the schematic. Once you have your HV right (As Dave said do that first) if the lines persist check that the voltages going to the pins of the CRT are in the correct range, and verify that control adjustments change them in the expected manner.

Ya know..... screwin around like that and letting the hv go up to 30kv is gunna
let out a buncha those little x-rays.... and they gunnaroastyernads.....

just sayin..... be crarful...... mostly cause ya can't see em comin.....

.

ok I am going to go ahead and take a leap of faith here with Timmy and GUESS what we are talking about.

I am currently uploading a video of a set that exhibits what I think Timmy is talking about ( I don't recall seeing any pictures or video). it will be done in a few..
One thing for sure if I reduce the brigthness control I can eliminate them.

IF its what I think it MAY be some kind of vertical retrace issue. Note the issue I see does not seem related to the color lever setting on the front of the set. It does seem related to the brightness and contrast settings. This would point to the luma signal from the video out where the vert retrace pulse is fed for vertical blanking during the retrace interval.

a wild guess could be assuming the level and duration of the pulse is correct, would be maybe an issue with the video out tube (poor gain)? I have no 1st hand experience with this being a cause but I have noticed it before, generally shows up on tube that are not it the best shape, hence I just assumed it was related to the condition of the picture tube. Perhaps a cut off issue. I do know that at least in the CTC-17 there was a transistor inserted into the vert blanking. I have never tried to increase the amplitude or duration of the pulse to see if this was indeed the issue.

Now that I have reversed myself and gone ahead and speculated, I will see if that video is done and will link it here.
I just checked the schematic, the vert blanking pulse is fed in at the plate of the video out (cathode of the CRT) so guess the gain of the vert out tube is not an issue, that leaves either not enough of a pulse or not enough cut off control of the CRT.


Timmy get that HV fixed.

here you go Timmy, don't leave me hangin'

I did notice that on the CTC-35 the vert pulse was fed into the grid of the second video amp (wrong phase for video out grid). Maybe that would be a more effective blanking, assuming its just that a weak CRT could use the help.

new link

https://www.youtube.com/watch?v=39DlVjo9hSY&list=UUxMsHgfGwCVtyRrqXVtll-g

Delete

come on Timmy don't go dark on me.

For some reason I can't make the above link work - takes me to Google sign in page.

This one seems to work(for me).

https://www.youtube.com/watch?v=39DlVjo9hSY&list=UUxMsHgfGwCVtyRrqXVtll-g

thanks for getting that to work. link works for me, but maybe I put it there after logging in? anyway hope Timmy can confirm this as his issue.

if link does not work can just you tube my channel Dave WM

thanks for getting that to work. link works for me, but maybe I put it there after logging in?

Yeah, that's what had happened... The link you posted was to the 'edit my video' type section within your account, (notice the /edit?o=U part), you must have grabbed the URL from within your account, not the published link.

The best link is just simply:

https://www.youtube.com/watch?v=39DlVjo9hSY

so silly YouTube doesn't try to autoplay the whole list of videos.

this looks interesting a two pulse blanking circuit

http://www.google.com/patents/US3247418

Note the pulse to the G2

yup i also had a problem getting into that link. when i posted what i did i had already pulled the chassis and i was going to go over the components i had put in when i first got the set. my first mistake was the doubler caps as they should both be the same but what i did was for a 250v 160uf i put 2-250v 100uf in paralelle and for all i know one of the 4 caps may have went bad and the voltage is not what it should be, its like batterys in series, one goes bad it pulls everything else down . resistors, and other fixed caps i put in i have to check. like i needed i think it was a .12 630v but moyers gave me a .1 and a .022 to make up this cap and i was told by someone here at karma that the .1 was enough so i had taken the .o22 out but i had more problems then what i had already and i think it was the drive lines issue that i have now. so maybe these caps should not be parralelled as i know some parts of certain circuits this should not be done because this may be a timing circuit . so all in all i didnt have the lines in the beginning but when they appeared they just got worse every time i turned the set on so clearly it could very well be the crap i put in this set and how i did it, paralelling caps, no.no, on my part. temporary may have been acceptable but not permanent. i will get back soon with an update...

So were the lines in the video what you are experiencing?

i am almost certain it was the lines because i had since got tired of the hv issue and even when i had taken the 6bk4 cap of i didnt get hv like i get now since changing the flyback. but yes i was more concerned about the lines and this is why i decided to go ahead and check my own work and fix the screwups or the should not have done crap. i never did get to the link you had sent.

just go to you tube and look up my channel

Dave WM

or just google

CTC-12 retrace

There is nothing wrong with putting capacitors in parallel to duplicate a out of production value. For instance if you need to replace an original .25uF 600V capacitor, you CAN replace it with a .22uF 630V in parallel with a .033uF 630V and it will work fine, not to mention be a more correct replacement, value wise than the .22uF part alone.

Trust me I use parallel caps all the time in my restorations, and they always work just fine.

ok got the video, yes they look like that with each line a different color and if i move the contrast i can make them almost not there. the vert hold if i make it roll there is lines but they are lines with dots on the right side they are somewhat different them the color lines that are there all the time. i thought the retrace lines are the ones that the lines go half way across the screen towards the right and at the right they end with what looks like dots. but just a still pic yes those are the lines im talking about, lol ,lol. so ill have to concentrate on a verticle issue weather cap and or resistors. i tried another vert output tube and was no change so i ruled that out. thanks for that video it was very helpful. oh and by the way the set on this page is the very one with all these issues,lol,lol....

Ok there are 3 parts that are used to cut off retrace.

You need to look at two resistors (100k,68k) and a .01 disk.

You need to check your schematic and find them, they go from the plate/transformer vert lead to the plate of the video out tube.

Its unlikely to be the problem, but its where you should look. I will do a video later showing where they are (one resistor and the cap is on the chroma board, one resistor is on the deflection board).

The more likely problem is just a CRT that is getting soft to the point where the setup bias is just beyond the point of the blanking pulse ability to blank it out (the CRT is blanked by the reg blanking pulse from the video signal AND the blanking pulse from the vert out).

It "may be" possible to overcome a weak CRT (or one with poor cut off) being the issue by the mod noted in the patent. I say "may be" since I am only speculating that the mod noted would generate enough extra cut off voltage to resolve this.

ok interesting info thanks, as for the crt it is original from 63 but tests good with good cutoff but i do hope its not the crt.

if it test good with good cut off then its likely to be one of the following

CRT setup incorrect (kine bias/drive pots)

AGC (too low)

Open resistor or cap per my prior post.

It has to be one of the above so there is no need to start replacing caps (like the .12 you mentioned before).

What is confusing is you said it was fine then you made cap changes, then it get worse each time you turn it on. That is a very odd situation.

This is why I do not recommend mass recapping as a rule, although I am having a hard time trying to figure out how it gets worse with each time you turn it on.

since the lines started it has got worse no better so when this problem started i looked into things to try to find out what may have been causing it. i didnt make any changes just that i pulled the chassis the other day to check caps , resistors, ect. the kine bias pot is 6k and measures good that was the first thing i checked. so then i should leave the.1 cap and the .022 paralled in place for the.12 that the sams says and what i took out.

I don't know the .12 you refer to, but I am pretty sure its not the problem.

I am uploading a video now showing the likely suspects, its 11min long so will take a while, check back in about 1 hr.

the old cap when i first got the set was a .12 600v and i put in place a .022 and .1 600v together in parallel. was not sure if this was a good idea from the start.

if the .12 was bad, then its ok, if it was not bad then its still ok, just not needed. Recapping as a way to fix problems is not a good idea. You may get lucky but you learn nothing. Better to learn how things work the diagnose the problem, esp with sets of this era, the caps are often fine, and recapping just introduces the possibillity of errors (wrong values broken traces etc..)

Besides what do you do after recapping and you still have a problem, or if it works for a year then a new problem, recap all again? so learning how things work is the way to go and what I think this forum can help you with.

Ok new video is up see part 2 regarding the parts that can be checked.

the old cap when i first got the set was a .12 600v and i put in place a .022 and .1 600v together in parallel. was not sure if this was a good idea from the start.

I think I would have just popped a common .1mfd. 600V in there to replace a .12 which is oddball. The general rule is to always go higher, not lower in both capacitance and rated voltage value, but the difference between these two would not be significant enough to warrant two caps. And I do believe that the capacitance adds when two are paralleled, but the voltage rating is compromised. I forget the calculation on that and may have it backwards. I hope one of the other members will elaborate on this and correct me if i'm wrong on the .1 idea.

great video and i found the cap and resistors as far as the disc i will have to change it because i have no way to positively check it and what is the voltage on that .01 disc cap? the resistors on the other hand well the 68k was found to be 69.8k and the 100k was found to be 100.8k both of which is well within range. so now if i can find out what the voltage rating is for the .01 disc ill change that just to be sure . the doubler caps being i have 4 in paralle 3 of which are the same brand but the 4th one is smaller and a different brand so i have 2 caps rated 450v 470uf i was going to put in place of what i have now and while it is a bit overkill at least they are both the same and there will only be 2 of them, just to rule out any possible problem with the ones in there now. im still debating weather or not i should leave the 2 caps in paralle that are .022 and .1 for the .12 that was in the set originally there are certain opinions about doing this with caps because one could go bad and pull down the circuit that its tied to so i would figure this could do away with any possible future problems since i dont have a cap tester on hand.

I would say anything rated more than 100v on the .01 should be fine. That being said its very UN likely to be the problem. Disc caps are very reliable.

I did some more checking on my set, the one in the video with the problem. . The CRT would not produce any lines in setup mode unless i advanced the red gun fully CW and then advanced the bias pot about 1/4 of the way. I tested the CRT with my CR-70 and it tested quite weak (well into the red zone) with very little cut off response.

So with that I presume my issue is a weak CRT (its not very bright either).

I suggest you try checking your CRT again, and if confirm that the CRT tester is working properly.

IF your CRT is good with a known good CRT tester, you should also consider checking the filament voltage at the CRT just to make sure the filaments are getting the correct voltage from the set. Again this is a long shot.

remember CRT testers are not infallible, just cause it says its good does not mean it is. The only way to be sure would be to check the calibration of the tester OR test it on a known weak CRT to confirm its function.

Before messing with the power supply caps you should just check the B+ voltage to see if its what it should be with a multimeter. I doubt a B+ fault would be causing the issue.

well i do have another set round screen with a very weak red gun the others are not that great either however i also have 2 more crt testers and get the same from the weak crt. and the set with the weak crt has a perfect picture and clear no lines, even though i have video issues with that one it still has a good pic. so with these testers i will go ahead and check this crt and the cutoff again but if it should show good cutoff i dont know where i will go from there. it certainly to me sounds like you know a whole lot more about these sets then i will ever know. on my bk440 which i have 2 of them and one is recapped and the cutoff the last time i checked on both showed the same and where it has the line on the right and left the test on all the guns were less then half on that scale but not at the quarter line but rather higher then the quarter itself.

I think I would have just popped a common .1mfd. 600V in there to replace a .12 which is oddball. The general rule is to always go higher, not lower in both capacitance and rated voltage value, but the difference between these two would not be significant enough to warrant two caps. And I do believe that the capacitance adds when two are paralleled, but the voltage rating is compromised. I forget the calculation on that and may have it backwards. I hope one of the other members will elaborate on this and correct me if i'm wrong on the .1 idea.

I suspect that the designer chose .12 over .1 for a good reason... I would leave the parallel substitute as is (if they check good).

A little refresher on series & parallel capacitors:
http://www.coilgun.info/theorycapacitors/capacitors2.htm

jr

I would say anything rated more than 100v on the .01 should be fine. That being said its very UN likely to be the problem. Disc caps are very reliable.

I did some more checking on my set, the one in the video with the problem. . The CRT would not produce any lines in setup mode unless i advanced the red gun fully CW and then advanced the bias pot about 1/4 of the way. I tested the CRT with my CR-70 and it tested quite weak (well into the red zone) with very little cut off response.

So with that I presume my issue is a weak CRT (its not very bright either).

I suggest you try checking your CRT again, and if confirm that the CRT tester is working properly.

IF your CRT is good with a known good CRT tester, you should also consider checking the filament voltage at the CRT just to make sure the filaments are getting the correct voltage from the set. Again this is a long shot.

remember CRT testers are not infallible, just cause it says its good does not mean it is. The only way to be sure would be to check the calibration of the tester OR test it on a known weak CRT to confirm its function.

Before messing with the power supply caps you should just check the B+ voltage to see if its what it should be with a multimeter. I doubt a B+ fault would be causing the issue. well i could take the 6dq5 out and run the chassis to check b+ but it may show ok but would it possibly show less under a load if there is a problem within the caps.

regarding the .01 ceramic disc cap could this cap be subbed with a .01uf metalized film capacitor ?

you can use a foil cap in place of the disc.

You do not need to remove tubes to check the B+ just find a B+ test point on the chroma board and turn it on, wait for raster to come up and see what it is.

yes i know i could do that but with the chassis in but right not its out of the cabinet i didnt know if it would have been helpful to check it out of the cabinet with the hot out but it does pay to do it with all hooked up. so ill stick with the disc as whats in there, as a replacement. i also checked the 2 1.5 meg resistors that are for the hv some say they must be matched i really dont know but 1 is 1.509 and the other is 1.602 dont know if this would have any bearing on the hv issue.

those effect the HV regulation circuit. No reason to suspect them unless you know the HV reg circuit is not working.

To know that you need to test it, using the shunt on the 6Bk4 and see if the current thru the tube varies with HV pot setting AND CRT brightness. You should get between .5 and 1.5 ma current from high to low brightness (raster). this will vary depending on the HV setting, typical is 23-25kv and should hold to within 500v when vari brightness (the shunt tube draws more current when the screen is dark, keeping the HV in check as the CRT load drops. as the brightness increases so does the currrent thru the CRT and the shunt tube current drops, this keeps the flyback HV total current and HV voltage constant).

I don't think you can check them for value in circuit and get accurate results as to how closely matched they are.

I do not recommend replacement unless there is a KNOWN problem in that circuit.

i did clip one end of the 1.5 meg resistors and got the reading above. i was told if i have to i could use 2 1meg ohm instead and it would change something minor with the hv adjustment but would still do what it has to. i still have the unknown problem with hv regulation and this is why i was wondering how important those resistors really are.

yes the crt is dark but still see the drive lines and i already checked the pots and they are in range. when i put the jumper back i will be able to adjust the hv but what is going on it struggles to regulate yet i can get it adjusted to 25kv but with the hv pot maxed. so ill have to check the voltages at the crt and hopefully ill get somewhere there.


do this, check the HV with a probe with the CRT brightness all the way down, does the HV pot adjust from say 20 to 27kv? If it does the regulator tube is working.

now set the HV to 23kv with the brightness all the way down. READ the shunt tube current and let me know what it is. Based on what you get I will tell you what do do next.

bright down the hv adjust does work and can get 23kv but only if the pot is maxed and on different scenes the hv drops off like it is not regulating and this is why i was wondering about the resistors. the hv adjustment dont have much gain to it and the reg tude does get hot like its working and in the dark if i raise and lower the hv adjustment the tube will glow with alittle blue to it depending on up or down adjusting and i have tried several reg tubes in the past and all the same result. but i will have to check the ma in that hv circuit.

i had posted some pics of the crt in this set if you can find it or maybe you have seen them with the blue marks that start at the anode button and has traveled down the tube and when i first got the set the blue mark was nowhere as big then as it is now and yet it tests good and there is no blue or purple glow to suggest a gassy tube maybe there is something going on with this crt thats taking to much hv , making the lines, i dont know but i do know that the mark at the button was just that when i first got the set and now its several inches down extending from the botton and several members had said it was a manufacturing thing in the glass but why has it got worse is the question.

bright down the hv adjust does work and can get 23kv but only if the pot is maxed and on different scenes the hv drops off like it is not regulating and this is why i was wondering about the resistors. the hv adjustment dont have much gain to it and the reg tude does get hot like its working and in the dark if i raise and lower the hv adjustment the tube will glow with alittle blue to it depending on up or down adjusting and i have tried several reg tubes in the past and all the same result. but i will have to check the ma in that hv circuit.

with the brightness all the way down what is the max HV you can get with the HV adj pot fully CW.

i can get just befor the red mark on the hv probe i think its 25kv but the hv will droop down to 19-20 kv depending on the scene. but again with the hv adjust maxed and all my other sets setup on the hv the pot is just alittle over the half mark.

ok with the brightness all the way down the max you get on the probe is 25kv?
with the HV pot maxed out correct?

yes

ok Now disconnect the lead from the top of the shunt tube, hang it so it cant arc to anything (it will have full HV on it).

CRT brightness all the way down are you still at max of 25Kv?

well i will tell you i have done this befor with the reg tube cap off but now the chassis is on still on top of the cabinet and each time i have done this it did go to around 25kv and also did it with the crt plug off as well its only once the crt plug is put back on then the hv drops and it has been said that something is loading it down. either in the circuit or the crt itself.

when you get it all back together if it is not working I will attempt to help you.
I can not with out going thru a specific series of steps in a flow chart like manner. Good luck with it.

ok ill get this thing back together and see what i have and i will get back to you and i really appreciate all you are helping me with dave and the last thing i want to do is to waste your time or anyone elses for that matter. thanks

No waste of time, you will get it, just sometimes a tough dog takes a very systematic approach to resolve. Hang in there. :thmbsp:
I will be around to help when I can.

well i will tell you i have done this befor with the reg tube cap off but now the chassis is on still on top of the cabinet and each time i have done this it did go to around 25kv and also did it with the crt plug off as well its only once the crt plug is put back on then the hv drops and it has been said that something is loading it down. either in the circuit or the crt itself.

If you are getting no more than 25KV with the reg cap OFF--then the HV ckt is not producing enough HV. With the reg out--it should make it to at LEAST 30K--unloaded or with no raster.

This might mean the drive is not good enough--or maybe the damper ckt is not working well enough, possibly that "boost cap" the one off of the damper tube--where the boost is taken from--is bad. BTW--I do NOT think the HV adj. will work at ALL--if the regulator is out of the ckt. BTW--not sure on this chassis--but SOME horiz. ckts, have a resistor that comes off of a positive supply, designed to keep the grid from going too negative. If it goes up in value--this happens...and you get low HV and other problems. It is likely to be a high value one--100K or more. I recall Jack Darr or someone, talking about this in an article--I think in a PF reporter magazine.

And--do NOT forget to check and see if the B+ is up to snuff. Not sure what it should be--but I would say at LEAST 375V...WITH proper load. Maybe more-much lower--and you WILL have problems ALL over the chassis.

well this chassis is a ctc12 clone and it dont have a boost diode, why i dont know but i guess design but the 15 has it. i did disable the hv pot from within the circuit and got a scary little over 30kv.

The circuit rca2000 is a hold down circuit designed to limit HV output incase the shunt tube were to not regulate. It takes a negative voltage from the horz blanker grid and thru a voltage divider applies it to the grid of the horz output tube. was not used until the CTC-15, don't know about clones. the defect that would take place is a break in the trace on the edge of the chroma board, that would upset the voltage divider, providing too much neg voltage back the grid of the horz out, thereby limiting the power thru the tube and holding back the voltage.

You find this by checking the grid voltage of the horz out, should be about -50v if its a lot larger neg like -65v there is a good chance the problem with the broken trace exist IF THE SET USES THIS METHOD.

This would also show up in testing the horz out cathode current (it would be low).

This failure can also effect the brightness control as the too large a neg voltage also feeds the neg (dark) side of the brightness pot.
you can also check pin 2 of the horz blanking amp. this is the pin that has a 390k resistor to ground if its higher that 390k then the

A simple continuity check can be done by check from ground to the resistor that goes to blanker grid. Just look for the trace on side of the chroma board that runs next to the horz out. its pretty thin and is on the narrow side of the board.

I hesitate to mention all this as I would prefer to simply diagnose problems rather than jumping on every known problem in hopes of guessing right.

But if you have the chassis you may as well verify the continuity.

you can also check pin 2 of the horz blanking amp. this is pin to ground should not be more than 390k if so its likely the trace has cracked. the sams shows 220k on the resistance chart, but thats due to some other resistance in P with the 390k resistor that goes from the grid to the ground.

ok the 390k resistor checks at 250k and the ground trace is good. 250 seems alittle low dont they usually go up in value. as far as the damper there is 2 caps off the damper which has been replaced and its a .12 250v and a disc n1500 4kv and there is a small disc n760 1kv sams says it a 22mmf to ground off pins 2 and 7 was not replaced. and l31 and l30 check perfect .4 ohms.

ok i just took the 390k resistor out of circuit and it checks .420 meg which im not sure how close that is to where it should be.

did not want you to take out of circuit to check. if you get 250k from pin 2 to ground that is all you had to do to check.

with this ctc12 clone where is the best place to test that the boost voltage is in place. sams says 720v is the boost voltage.

ok here are some voltages, i hope im right with the wires here. ok the yellow with colors is cathode,blue 280.9v green 276.8 red 245.3. g2 white with colors, drives maxed red 760v blue 757v green759v. g1 solid colors red 195.7v blue 186v green 193.6 . with the set on warmed up bright down hv adjust maxed cant get no more the 23kv it does vary via the adjustment so its working but something is wrong in the circuit. i also tried pulling the crt plug off no change in hv. however i didnt yet pull the 6bk4 cap off to see if the hv goes up the last time i pulled the cap off it did go up much more. i also checked the ohms again on the hv adjust pot and its good. so i guess the boost voltage is there as it shows on the maxed drives.

remove the top plug from the 6Bk4 brightness down (crt dark) check HV again. be ready to pull the power plug if it starts to go north of 27kv
remember the top plug cap of the 6bk4 has full hv (so make sure you have it hanging away from any grounds).

What is the condition of the HV rectifier tube--AND..is it getting proper filament voltage ? because if it is weak or not getting proper filament drive...you WILL get low HV.

What is the condition of the HV rectifier tube--AND..is it getting proper filament voltage ? because if it is weak or not getting proper filament drive...you WILL get low HV.

I agree with this here.... Also, when the 'Scene' changes and the HV goes down
does the picture width come in, or remain full....? Even a little....? If no, then
I'm even more inclined to think about the hv rect.

Also, I have never checked this but I would assume that a weak tube would
be conducting less current, so.... less cathode current right....? Basic....
So how could a tube conducting less current be dragging down HV....? It should
not.... I imagine when this is fixed, the picture should be a good bit brighter...

And in the videos the scanning lines are nice and defined... Not really a bad
tube looking..... right...?

Also, Sams usually has brightness settings, specified for their measurements...
you should probably look at them.... follow them....

Also, if recapping and on each part you "round" values up, down, or sideways....
after a few parts yer gunna have an entire tv with parts 20% off.... not good....

Be careful how you chose to determine filament voltage on the HV rect. You might
just wanna get a new one off ebay...

.

remove the top plug from the 6Bk4 brightness down (crt dark) check HV again. be ready to pull the power plug if it starts to go north of 27kv
remember the top plug cap of the 6bk4 has full hv (so make sure you have it hanging away from any grounds).

ok ill pull the reg tube cap off. the 3a3 i have tried others and also tried a solid state 3a3 .

ok 6bk4 cap off bright down was hissing and was at 28kv then pulled the plug. didnt wait for it to rise anymore. can see the 3a3 filiment lit.

Generally, you won't see it..... And at that voltage (28kv) you won't see the x-rays either.

.

ok so now we know for sure the HV is working and can focus on the regulator circuit.

you need to connect the anode lead back up on the regulator, then get some leads to the cathode and grid for the shunt tube. check the voltages of those leads compare to the sams.

There is not much to go wrong with a CTC-12 regulator. I would suspect the pot but you said it was tested and (you actually tested the pot with a meter for resistance and wiper function). the 2 resistors are fairly close, that leaves the .0033 cap from cathode to grid. if it was leaky at all it would upset the shunt bias.
Note the cap is a disc cap and not likely to be bad, but its pretty much the only thing left to check.


OR you have a gassy shunt tube. do you see any purple glowing from the shunt tube?

ok so ill check the sams for the voltages on that tube. i also tried several other new reg tubes including an old one that has turned brown and never got a better result. just yesterday i took the single wire off the hv pot and and checked the ohms and the wiper, i think it was 500k and it varied just fine up and down. the .0033 i changed twice thinking one may have been bad. i use a fluke DWOM and it does work well thankfully,lol..

if you have done all that them I am out of ideas. It sounds like a regulator problem. Voltage checks should narrow it down.

Just to clarify

you have max of 23kv with the CRT dark and the HV pot maxed out.

You remove the cap from the regulator and it goes over 28kv

You have tried KNOWN good shunt tubes.

You have check the HV pot (and its ground is good)

you replaced the .0033 grid to cathode cap.

ok #5 390v # 2 402 on the reg tube.

if you have done all that them I am out of ideas. It sounds like a regulator problem. Voltage checks should narrow it down.

Just to clarify

you have max of 23kv with the CRT dark and the HV pot maxed out.

You remove the cap from the regulator and it goes over 28kv

You have tried KNOWN good shunt tubes.

You have check the HV pot (and its ground is good)

you replaced the .0033 grid to cathode cap.

yes to all ...

been thinking about it, maybe the regulator is ok, just a little aggressive on the high point of what it will allow the HV to go to.

so check the voltages on that tube and check the current thru the shunt wire, see if it varies from .5 to 1.5 as you adj the HV pot.

voltage look ok, now to check the current disconnect the shunt wire and get a reading. adj the HV pot and note the high and low points.

do this

dark screen, current at HV low setting, current at HV high setting.

normal brightness screen, current at HV low setting, current at HV high setting.

all readings do vary, dark screen low hv set 1.64 high hv set 0.93 bright up screen hv low1.16 high hv set 0.20

all that seems correct.

and yet the HV varies from 23kv to 19kv based on brightness?

One last test, check the cathode current of the 6JE6 (or is it a 6DQ5) and check the screen and grid voltage of that tube as well. should be about 140v on the screen and -50v on the grid.

yes based on brightness as well as scene changes, white scenes it drops wont regulate to keep it up,this is baffeling. ok ill check the cathode currant and the other on the 6dq5.

the way is should be working is the HV should hold up until the current thru the shunt tube drops to zero. since the lowest you saw as .2ma thru the shunt, I would have thought the HV was still holding.

the cathode current should be 180-205 ma, a lot to do with line voltage.

the screen should be around 140v

the grid should be -50v

6dq5 pins 1-5 -56.2 pins 4-8 142v and the cathode currant is 190 ma

ok #5 390v # 2 402 on the reg tube.

did you mean #5 and #1?

no that was the regulator tube #5 390v and #2 402v i think its on the previous page.

you should measure the grid and cathode of the reg 5 and 1

something odd here i tried to discharge the anode of the tube when sliding the chassis out and i have yet to get a small spark it almost seems as if its not holding any hv. chassis ground to anode with the crt plug on, no spark, could there be some connection here because i am lost i used to get a small spark but i dont see it now. what would go bad in this tube if it tests good in a areas?

you should measure the grid and cathode of the reg 5 and 1

5 and 1 the currant or voltage, if voltage i just would have to do # 1 5 i did already.

If the picture tube is not holding a charge.... Look for leakage from the 3a3 heater
windings on Flyback to ground....?

And check out what Dave said about measuring the grid and cathode voltage on the reg. tube.

.

you reported back on 5 and 2 that is why I quoted you. are you sure you did 5 and 1 votages

im sorry the #1 i did check voltage not #2 because it looks like the heater is 2. so #1 is 402 v

ok just checking cause the filament may have 400v as well (its kept high relative to ground IIRC to avoide cathode heater break down).

well even though the hv dont regulate properly it still will produce a decent picture so if i could get to the bottom of where the lines are coming from if its not hv related then ill just leave it as it is.

im just guessing here but maybe the hv is infact ok but rather the overdriving or whatever i should call it maybe pulling the hv down beyond what it can handle. the bias cannot be raised at all the lines get worse and the screen blooms. if i set the contrast to make a sharp picture the lines seem to go away but just move the contrast a little bit and the lines are back. so with the bias all but off and the 3 color drives counter and with a b@w picture there is some lines visable but bearly. i really dont know im just grabbing as this point.

I have been re-reading this entire thread, and have a few things to look at.

You mentioned repairing mistakes in the focus rectifier circuit, and that you
replaced the flyback.... I would suggest that you revisit all the work done on
these two items to be extra sure there are no mistakes made in the wiring.

The flyback was it an original....? Are you absolutely sure the correct wires
are put in the correct pins...? A mistake in the parts near or connected to the
damper could possibly be giving you bad signals going to the blanking circuit.
Incorrect pins could also be interfering with the field strength in the flyback
during any part of the charge discharge cycle....

If the flyback was a replacement, or even if it was from a parts set, you should
check over each connection with ohm meter, or replacement part notes to be sure
the same pin numbers correspond on both new and old part.

If you have checked the work around the two areas you previously worked
and the wiring is correct, then carefully check the parts and voltages near
the items in yellow on the attachment. And replace the caps in green....

If you have already replaced the caps, and found good continuity or if you have
the entire sams with resistance checks for the coils, then you need to check
those caps to be sure they are correct values and voltage ratings.


.

well this is what i have as of now , i did resistance checks of the tubes on the chroma board and the vert board compared to the sams some are alittle high but not much however i would say they are all very good or close. but v21 and v23 are 6gy6 tubes and pin1 on both should be 1.9 ohms but i am getting around 150 ohms and it changes with turning the color knob on the front of the set, there im lost. also pin 7 on v21 should be 1.9 ohms i get 2.0, so thats ok v23 it should be 14 ohms im getting .9 ohms so i am really lost but this could be the problem with the drive lines and down the line it may even fix the hv issues as well. it almost seems that something may be shorted for that ohms reading to be so high and to get a varying reading when raising and lowering the color control. the resistance page of the sams dont state anything about the color control changing anything.

I have been re-reading this entire thread, and have a few things to look at.

You mentioned repairing mistakes in the focus rectifier circuit, and that you
replaced the flyback.... I would suggest that you revisit all the work done on
these two items to be extra sure there are no mistakes made in the wiring.

The flyback was it an original....? Are you absolutely sure the correct wires
are put in the correct pins...? A mistake in the parts near or connected to the
damper could possibly be giving you bad signals going to the blanking circuit.
Incorrect pins could also be interfering with the field strength in the flyback
during any part of the charge discharge cycle....

If the flyback was a replacement, or even if it was from a parts set, you should
check over each connection with ohm meter, or replacement part notes to be sure
the same pin numbers correspond on both new and old part.

If you have checked the work around the two areas you previously worked
and the wiring is correct, then carefully check the parts and voltages near
the items in yellow on the attachment. And replace the caps in green....

If you have already replaced the caps, and found good continuity or if you have
the entire sams with resistance checks for the coils, then you need to check
those caps to be sure they are correct values and voltage ratings.


.

as far as checking connections to and from the fly i did that already and the fly was a newer one when i got the set not the original. and i went over everything i did and find nothing. the schematic is alittle different then the one i have as i dont have vert centering on this chassis, maybe the one you have is an RCA. but the green caps you speak of it looks like i replaced them you have listed at the time i was trying to figure out the hv issues.

i have what looks just like a ceramic disc cap but its a 6mmf npo 5% i have to replace is there any other i could use in place of that. and what do i look for there is pf, nf, .0 .00 and so on dont know what that means exactly.

why are you replacing the cap?

well i took one leg out of the board and it fell apart so i dont know if it was bad but now i have to replace it.

oh. BTW sometimes the SAMs resistance charts are just wrong. missing decimals or just wrong, and also sometimes they resistance numbers are influenced by pot settings. This should be noted but not always done.

Lastly they are only a guide. if something does not match up, its best to review the schematic and see if the measurements can determined by looking there. in your case the 14ohms does not make since prob should read 1.4 ohms. You can see this if you look at the schematic and trace the pins to the ground.

again if this is the area you are looking into, I would assume the set is not demodulating the color signal so you are getting BW only?

yes i figured as much because i have found mistakes in the sams. and yes its the silvertone still, i think ill just try to get that 6mmf cap and maybe put it back together and maybe assume the crt is bad.

I think that would be best.

mmf is pf

so that would be just a 6pf any zeros like .0 , or .00 and would that be 100v or more. in a disc type or something as long as its 6pf.

Go to google and search "how to read capacitor values" you will find many links.
http://www.wikihow.com/Read-a-Capacitor This is just one, there are many...

uf 'u' is a multiplier, pf 'p' is a multiplier.... your 6pf cap usually will not have any
zero's. the 0.6pf would be wrong, and 6.0pf is usually not written. Anything
above 100 as in 600pf for example 6,000pf is usually not written as it cancels out
the 'p' multiplier.... (not really cancel, just not written) refer to the schematic
for voltage rating, as you stated, my schematic is a generic ctc-12 off the internet.
600v if ceramic is safe.... be careful about removing just one leg of ceramic caps in
a pc board, especially old ones, they are sometimes brittle, and not polarized,
so you don't have to worry about how to put them back....

On that page I referenced, down at the tips area, 6,000pf there is a convention
for writing values, possibly derived from scientific notation, or international
scientific standards for writing values. This is why you may or may not see a value
written in a specific way...

.

c121 is the cap 6mmf and sams dont have any voltage marked at all.

Sam's will have a note that defines what caps are when they don't have a specific
voltage listed.... just look around....

.

i found a reference in the sams that the chroma reference osc is .2 volts and looking at the schematic a test point shows 30volts on the #7 pin so i guess 50 volt cap would do but how would a 22pf be instead of the 6pf ?

If it's a timing cap in an osc. circuit then changing the capacitance is a sure way to mess up the circuit's operation

oh great, lol, i dont know, time to toss this set out the window and into the fire pit.....does anyone know if this cap would compromise the timing, i just want to put this thing back together and leave it now...

you should just get a 6pf, if its the one I think it is I don't think it will matter, but it makes no sense to go nearly 4x up in value. Try it and see.

you should just get a 6pf, if its the one I think it is I don't think it will matter, but it makes no sense to go nearly 4x up in value. Try it and see. thanks dave

ok an update on this silvertone, i found that after changing the 1st@2nd video tube the lines are i would say better then 90% gone, but of course i still have the hv that just wont regulate. for the 6pf cap i used 2 50volt caps rated 2.2pf and 3.9 pf in paralle to make 6.1. and the tube was the 6aw8a for some reason it is much, much better unless there is an issue in that area and being each tube is somewhat different then another maybe resistance was somehow corrected if this is a problem there. the hv not regulating is very weird as i again tried several reg tubes and also tried a solid state 3a3. also checked the crt ground and its fine so i guess its leave it alone for now. could the crt be gassy but still show it tests good and not show a purple glow in the neck and still produce a good pic but yet effect the hv in a regulating way ?