I decided to tackle this set , I can't believe how many tubes are messed up in it with shorts/gas and grid issues , amazingly one 6GH8 reads ok , I've replaced most of them with nos tubes ,there was a 2av2 in the 1v2 socket , would that work ? it was bad anyway so I put a 1v2 in.

the circuit breaker was replaced but instead of being installed wires run out to one mounted to the back , also theres an electrolytic can with wires running from the original wires , it just lays on the inside side of the set , these are things I will have to properly repair.
when and if I get it up and running should I adjust the hv control for less voltage to anode so the fly doesn't get pushed as much as it could be ?
what should the anode voltage be roughly ? I used to know but don't remember , I don't work on color sets enough.
also the selenium on the convergence board should I be worried about it ?
there are so many orange drops in it that I wont touch them unless theres some kind of issue in that section.
anything I should be expecting or know about like the power diodes or other issues ? I don't see a degauser wire around the crt , just glanced at the schematic and don't see one
mike

I think the anode voltage should be in the 22KV range if everything is working correctly. Check your input thermistor (inrush limiter) if you have one. The leads like to come apart from the body of the thermistor. The resistance cold should be on the order of 10-15 ohms or so.

adj the HV will not do much to the flyback as it uses a shunt tube, and if working it just absorbs the excess current. there is an eff coil on the chroma board that should be adj for min current, this is all covered in the sams.

Leave the Se pack alone on the convergence, I have found that most of the time they are fine, you will know if the convergence does not work.

the 2 vs 1 in the focus circuit, the 2 was used in the later CTC-16 the 12's had a resistor in the filament circuit of the focus. If you see a resistor on the focus tube socket then it prob needs the correct tube the 1V2.

These sets often work just fine as found, I have several that have the orig filter caps. Sound like at least one may have already gone so I would at a min restuff that one. The film caps in the vertical circuit sometimes give trouble they are HV types 1600 IIRC. so if you have vert jumpiness or odd vert behavior then those should go. .0082 is the biggest offender as it takes the most punishment. Right off the plate of the vert out.

i will replace any film caps that are not orange drop or brown drops just to be safe , I just did the .001 at 2000 volts with a Sprague orange drop rated at the same value and voltage , the original is one of those that are in like a ceramic tube and didn't want to chance it but will test any that are removed for the fun of it just to see if they are leaking, I think there is another 2000 volt cap in the audio , I think I have a replacement for it too.
I never attempted power up due to the issues I already mentioned ( circuit break , electrolytic ) plus with all these tubes that are not good it really would have not been pretty , the 6dq5 was in bad shape so its hard to say if it would work with it anyway.

I don't think there is a thermistor in the set but will check anyway

the ones in the vert may be bad even if orange (and prob if brown). the symptoms will be poor vert lin and maybe jumpiness.

The .001's are good to replace, I read somewhere the one on the primary side of the vert out is there to decouple any horz noise that is leaking back from the yoke windings.

I think you are right about the thermistor, I don't recall seeing degaussing circuits until the 16's

If you care to you can add a jumper wire off the cathode of the horz out tube. I routinely do this to make cathode current checks easy. I just snip the lead that goes the ground and add a length of insulated wire to that pin on the tube socket, then lead it out to the back of the chassis with a spade type connector that can be screwed down after checking current.

I also will replace the caps that are often in the AC inter lock, may be bumblee bee in there across the line.

There are 3 caps in the grid circuit of the 6GU7 diff amps. One of them that rest right between the tube and a power resistor is almost always weak when tested on a old school cap tester. If I have the chassis out I generally replace all 3 of those .01's.

one last thing to check, there are a couple jumper wires on the chroma board often are rotten and will break right off. If this happens the screeen will be tinted one solid color like the screen drive is turned wide open. I have seen a lot of these break so its a common problem. You will know for sure if one of the big power resistors is cold on chroma board (one of the wires feeds thru that). They can look OK but still be broken. A slight tug upwards will reveal that.

Ok you guys would know this has a 21FBP22 in it not the 21FJP22 as listed in the schematic / sams , is this an older crt ? any advantage or disadvantages ? it looks like admiral date code 63-11
ok I will replace the caps in the vertical section as suggested , the set doesn't use 6GU7 tubes ,uses 6GH8 chroma bypass amp/color killer , 6JU8 chroma sync phase det killer det , 6GY6 z demodulator , 6GY6 X demodulator , 12BY7 Video out , 6EW6 burst amp , 6GH8 chroma reference osc , 6FQ7 b y amp r y amp , 6FQ7 horz blanking amp g y amp , that's the color board.
the jumped electrolytic that I mentioned had a hand written installation of 1979.

heres a question can I replace that electrolytic 160uf @ 250 volts with a 250uf @ 350 volts or a 470uf @ 250 volts or is going too high going to mess things up ?

he did something interesting , its a multi section can and all the values were connected together to make 140 uf which is 20 uf too low but it must have worked or was close.

what pin on the horz out are you referring to and if it is too high I have to change some resistor / resistors ?

oh yeah the .0082 @ 1000 volts could I put a .01 there ?
mike

The CRT's are the same. One has a bonded safety glass and the other one does not. Some have a clear safety glass and others are frosted and tinted. You could use a 250uf cap but would be better to use something closer. The voltage rating of 350 is good.You can always go higher but never go lower.What the tech did was OK.The tolerances of those can caps are usually 20% either way

surprise surprise surprise as gomer pyle would say , I tested the 3 capacitors I removed , the .001 @ 2000 volts is ok , the .047 @ 600 volts is ok and the .01 @ 400 volts is ok , so looks like replacing others would be a waste but I will check the ones that are known to go or be bad , looks like I'm just going to do the electrolytic capacitors since one was bad in 1979 I wont chance the others and slowly power it up , I will check power resistors and anything that might not look right before doing so.

so this set has a non bonded safety glass (21FBP4) ? , if that's the case it sure is tempting to clean it but a lot of work , theres is a couple spots that look odd , I thought maybe it was cataracts but this may be just dirt , hopefully it's not annoying while watching .

sorry I don't have pictures and step by step on this restoration.

mike

I would stick with the 0082 if that is what is there, and go high on the voltage, so if its a 1600, I put in 2000, the price is about the same and the fit will be better anyway as old caps are larger than new ones.

sorry about the 6Gu7, I should have checked, the caps that have been bad on those is the .01, its right behind the 6FQ7 that is close to the middle of the board (not the one on the end), but I replace them all anyway. I can say that its hard to tell if there was any change (the bad test was the fuzzy eye opening on the value check, leakage tested fine).

I presume you are checking the caps with a old school cap tester that can apply working voltages, those little hand held DMMs are worthless when checking caps since the failure mode generally does not show up at the low voltages they use. I replaced the .001 simply because my cap tester maxed out at 450v so I could not check them at the rated voltage.

Most of the time the film caps are ok, The ones that have given me trouble in the past have been those few in the vert circuit. I generally dont do mass recaps on sets of this era without at least trying to see if it works (that way you have a base line to compare to).

The issue on mass recaps is the introduction of user error, if you are good at diagnosis then you can generally find the problem but if not you can make a real tough dog out of what may have been a working set. RCA with its PCB make wiring errors hard to do, but there is still the possiblity of value errors, .001 for a .01 as an example.

What I do is when replacing (that I think may be a problem) is remove the cap, test with the cap tester, if bad I will leave the cap tester alone and check the new cap going in (always a good idea, I have had bad brand new caps). By leaving the cap tester settings unchanged I compare the value that came out to the value that goes in (even bad caps will give an indication of value on the old school cap tester). If I do not have to adj the settings much then that is a double check that the value is correct (besides just reading the cap values). So you not only check the part going in (value and leakage) but also confirm the value is correct. This is esp helpful with the new numbering like 103 for .01 etc...

yes old tester and applied voltage to caps , I will do the vertical caps to be safe , one of the annoying things is to pull something apart , put it all back together to find you have to open it up all over again.

one board (either the color or horz vert ) clearly says rca on the underside , also the sams where it points out parts locations in photos shows a color board that has bigger tubes then whats inn the set and schematic and tube location in the sams.

On the non bonded CRT's, they have a rubber gasket around the edge of the safety glass that oozes an oily substance that gets on the CRT face and inside of the safety glass. Unfortunately, the only way to clean it is by removing the CRT. I did it with my '67 Admiral roundie because it bothered me but it may not bother you. I would just leave it to very last after you get it running.

JC what kind of cap tester do you have? have not seen one that can do 2Kv in the leak test.

On higher hours RCA clones I'd check all the caps on the color board. I have seen some sets where a good portion of the orange drops there were bad, and the .01 orange drop nearest a tube actually was split open!....It was not shorted, but it did not have a defined value when tested.

I will check other caps to be sure , the previous owner did install a fan that looks like it might be from a record player so it was kept cooler while running then sets that didn't have a fan , I guess it would explain why there was so much dust under the chassis , normally I find it cleaner there , this fan pushed air around in there so it helped keep the air circulating , the cover to the hv / fly is not present , I'd guess to help keep things cooler, I don't see any signs of things being over heated, I remember years ago when fixing sets for neighbors seeing caps that were orange drop near a tube and they had that burned look on the side .

I guess I'm going to have to use the 470uf in place of the 160uf or keep the replacement in and check if it gets warm or hot , I don't have anymore caps to replace with unless I waste a 100uf @ 450 volts hooked to two 33uf caps or a 47uf , the circuit only requires a 250 volt cap so I'd be wasting the 450 volt cap .

If that 160uF cap is part of a voltage doubler circuit (which was common around then) I would recommend keeping it the same value as the other doubler cap...I'm fairly sure there is a reason why all doubler circuits I've seen use the same value for both caps.

well here is the latest , going through resistors and not finding anything really bad off except for one that is 150 ohms and its 230 ohms and another that is 1k and it reads almost 2k , haven't gone through the capacitors but if they are like the ones I removed I expected to have leakage and they didn't the others may be ok too but testing will show for sure.

mike

went through the capacitors in the vert horz board , they were all checking good , I almost gave up but then found a .47 with minor leakage that goes to the vertical hold control that changed my mind and the other which had a good amount of leakage was .1 in the agc section, I did find it interesting that on some when I de-soldered one leg of the cap to test it the end still connected would move a little on the board , I even found this to be true of a resistor that I never heated the pins , is it just because the solder joints are old or is it just because some weren't strong from the factory ? any ideas ?

oh yea the ctc12 clone how i remember, in my sears silvertone 1963, changed so many caps and it still has issues. maybe one day it will be close to perfect which these sets were never perfect but better then it is now. if its not verticle its hv and if its not all those its cant get the color just right, ahh one day . good luck with your set. those solder joints can move because the joint is old and needs to be reflowed or the foil trace has come loose from the board it self and you dont want to tear the foil otherwise you will be putting jumpers in to correct the connections of the traces that broke.

there were a couple others I found , a ground to the board of the convergence was loose , a ground to board somewhere else was loose , so as I go through the set I will be checking connections , the very few terminal hand wired ones seem ok , boards were a mistake .... perhaps you just need to redo all the solder joints on yours?

mike

Well I'm pretty much done going over the set , seems that the orange and brown drops are ok except for a couple I replaced , I didn't touch the if boad , I figure if theres a problem I will but left it alone , theres only one orange drop on it .
so as soon as I reconfirm that resistors I wasn't sure if they were ok or not I will give it a slow power up on the variac and then hope it works and will wonder how much adjusting may be needed as far as convergence.

what was the pin on the horizontal output tube I should measure the voltage on and what the voltage should be ? ( probably says it in the schematic )

mike

went through the capacitors in the vert horz board , they were all checking good , I almost gave up but then found a .47 with minor leakage that goes to the vertical hold control that changed my mind and the other which had a good amount of leakage was .1 in the agc section, I did find it interesting that on some when I de-soldered one leg of the cap to test it the end still connected would move a little on the board , I even found this to be true of a resistor that I never heated the pins , is it just because the solder joints are old or is it just because some weren't strong from the factory ? any ideas ?

On the old RCA chassis, it's not uncommon to get fractured solder joints. I ran into this on a Silvertone combo set I worked on a couple of months ago, which had a couple of bad connections on some jumper wires that I needed to re-solder. Fractured solder joints can be caused by either repetitive mechanical stress or by thermal cycling (typically thermal cycling in an old TV set). Bad solder joints are also common where the PC boards solder to the chassis to pick up ground. Be sure to check these as well.

Well it is up and running , when slowly powered up it came to life , needs adjustments as you can see with the convergences , when it came on the picture was a blur , I tried another 1v2 and still a blur , I tried the focus and almost got a clear image but still blurred with the focus adjustment rotated as far as it would go in, so I then said what if I try the 2AV2 that was in the set to begin with - bingo a better image that focused well , odd since the tube chart and sams says 1v2 and in the set laying loose was a 1v2 admiral tube , this 2av2 doesn't even test well but seems to be working , the fly gets hot or warm , not too hot to touch , should it get warm/hot ?
there is also way too much green , tint has to pretty much go all the way to one side to get sort of normal colors , should I try the green drive or the green screen ? I can tell you the black and white image is pretty much grey that's why I'm unsure which to decrease for better tint .
is the blue issue the blue lateral or the convergence board ?
any other tips ?
the pictures show better then what can be seen in person as far as the color goes , the image is much sharper and detailed in person then the pictures show, looks like it has a clearer more detailed image then my zenith did or my friends silvertone.

thanks

a good set up and your done!crt looks ok so now just to a purity and convergence procedure and enjoy.

i don't recall purity tests , I will have to look it up , its on my color generator along with the dots and boxes but I don't recall what I'm supposed to do on the set , the screen or drive controls, convergence I know except it may be lateral needs adjustment too , wont know till I adjust the convergence board

check purity 1st before moving on to ANY convergence (static or dynamic).

just watched a couple youtube videos on this subject, I will try to do everything without moving the yoke and see where I get , if worse comes to worse I will move the yoke to make sure red is centered and go over the whole thing again , now with the these screen adjustments I should take the weakest color and turn it up as much as it will go and then take the others and make a uniform picture closest to grey as possible correct ?

in the past when working on color sets all I had to do was minor adjustments on convergence upper right , lower left etc

mike

On the screens: turn brightness to min, flip service switch to collapse vertical to single horizontal line, turn screens down until line goes away, turn up red until a faint red line just starts to appear, turn up green until line becomes yellow, turn up blue until line becomes white, return service switch and brightness to normal then check image with color off to see if gray scale stays gray. If it is tinted adjust color drive controls for proper gray scale.

Your blue lateral is indeed off in the pics. Use the static adjustments on the convergence yoke and the blue lateral to eliminate color fringing in the center of the screen. If there is objectionable color fringing away from the center of the screen use the dynamic adjustments on the dynamic convergence circuit board to reduce them as best you can.

If the gray scale is good and the tint control does not have enough range then the drive and screen adjustments are NOT the problem; there are problems in your color demodulator that may or may not be solvable with available demodulator adjustments.

what was the pin on the horizontal output tube I should measure the voltage on and what the voltage should be ? ( probably says it in the schematic )

mike

This is the second time in this thread that this question came up as someone explained the way that they do it, but I hope that we can get some elaboration on what I have heard is a very critical measurement on these old color sets. I don't think that you are going to measure voltage, but I may be wrong. I think that it is a current measurement. With that being said, people using "amp clamp" meters could do this much differently than those using any other meter which must be connected in series with the circuit in question. Either way, a remote way of keeping an eye on this is highly beneficial.

Also, I have read that it is a good upgrade to install a fuse in this same circuit to avoid the evident damage that can be caused by something going wrong. So, if we can get specifics on the voltage or current measurement on which section (plate, cathode, grid), as well as some ideas on a good fuse size, I think that it would help a lot of the growing crowd of vintage color TV hobbyists.

I do have a rca wr-64a color bar/dot/crosshatch generator that I never used , I opened it for inspection and see a .005 dic exploded in the power section , I replaced it and its twin but the thermistor or whatever it is looks like part of it is missing so I'm not sure what the part number is and if it will work , I put it on a variac and there is oltage coming through but will let it sit overnight to help reform the electrolytics if they need to be , the one that is cardboard I should just replace anyway.
if it doesn't work I will have to use my cheaper b&k model 1230 digital i.c. color generator , it has purity , dots , crosshatch, gated rainbow and color level.

I looked on the schematic and HOT shows pin 3 and 6 at 200ma and pin 4 and 8 at 18ma 145v , pin 3 is the cathode as far as I know , so to measure the ma would be a pain without running a bunch of wires from under the chassis temporarily to measure it , but once measured if too high how do you get it down ?

In any RCA based color set it should SOP to measure HO tube cathode current(IIRC there should be a .47uF cap in parallel with the current meeter) and adjust the linearity coil for minimum cathode current. I prefer to follow the Sam's horizontal adjustment procedure, for a any given set, which usually has you adjust the horizontal oscillator for optimum performance prior to minimizing cathode current in the HO tube. It should be set to 180mA(IIRC) or lower if possible. Some roundys had a 250mA (ie. 1/4A) fuse in series with the cathode of the HO tube. IMHO it would not be a bad idea to add such a fuse mounted above the chassis...It would protect the fly from an horiz osc. failure, and allow for easy points to connect the meeter to for measuring the current.
RCA based HV systems have a tendency to blow out their flybacks from running too much current through the HO tube...Which is why replacements for RCA roundy flybacks are especially scarce compared to other flys.

You have a good flyback, Please don't waste it.

forgive me if what I'm about to say sounds stupid but I looked up the data on a 6DQ5 , it says the cathode is pins 3 and 6 , the schematic for the set shows pins 3 and 6 to ground and it says 200ma , so I am to measure between pin 3 or 6 to ground to get the ma ?

I break the connection to ground run it through the meter back to ground or I measure another way ?

or are we talking another pin not 3 or 6 ?

I only did ma once with a porthole and it was measuring one end and the other of a resistor and I got my ma reading and was able to reduce it by changing the value of the resistor, so on this color set to reduce it I touch the lin ?

don't put a resistor between ground and the pin to reduce?

I can tell you from the crosshatch that lin and width are adjusted so things are proper.

on the blue lateral I fixed that and I think I got the screen settings right , will have to go over it again to be sure.

mike

You might find a jumper to remove that connects 3 and 6 to ground. You break the cathode and then you measure the current there to ground. I have a ctc 10 and 11. All Horiz out cathodes usually go to ground

Wow, it lives. That set likely sat in that unheated garage for most of its life, so it saw extreme hot and cold along with humidity. It wasn't turned on for at least 25 years that I know of before you got it. According to my grandmother, that set might have been one of my grandfather's garbage picks.

so disconnect pin 3 and 6 from ground , hook the meter up and measure pin 3 and 6 to ground without it connected to ground ?

njroadfan he did install a fan , its a record player motor with a blade , he also noted several tubes replaced in 1972 and electrolytic replaced in 1979 that still works , just about every tube had to be replaced , the film caps and resistors held up , I replaced all but one electrolytic ( the one he put in ) to be safe .
I bet if he garbage picked it it was put out there because of the tubes it needed in 1972

mike

My grandfather was good about leaving notes with dates of install/repair on them. In this household we usually put the date of purchase on the manuals of electronics and appliances continuing his tradition. Thats mostly so we can curse more when it breaks well before it should.

too bad he or the previous owner removed the legs , you can see underneath where the metal thingies were screwed into the bottom for the legs to screw into
maybe if I can find legs and the screw thingies I can add them

ok had I read the entire sams I would have seen they explain how to do the cathode , they also mention how to do the hv regulator but I don't know if I want to mess around with that since I don't have a microammeter,
they do say adjust the hv control for 23kv at the anode , also they mention when doing the grey scale to turn the kine bias fully counterclockwise and then go on to the screen controls, they didn't say adjust so you get red to turn to yellow and yellow to white or grey , that is very helpful Electronic M , I thank you.

that 6BK4 sure has a blue glow inside it

mike

too bad he or the previous owner removed the legs , you can see underneath where the metal thingies were screwed into the bottom for the legs to screw into
maybe if I can find legs and the screw thingies I can add them


The "thingies" you refer to are leg mounting plates and can be found at most home improvement stores such as Lowes, Home Depot. You should buy plates that accommodate angled legs. The tapered legs can probably be found at the same type store or an unfinished furniture store. Some even have the brass caps on them. Not sure of the length of the legs on the Admiral. Someone on VK must have a CTC-12 type table model color set w/legs of this vintage and provide measurements.

-Steve D.

I may have a set of those angled leg plates. Probably some legs too.

Found them. The legs are 60's NOS made in Japan, my dad bough them by the case full when I was a little kid.

http://i452.photobucket.com/albums/qq245/Kuehn/TVlegs_zps2b92d0a9.jpg?t=1389253404

What do those legs measure ? they look a bit short for this set or am I wrong ?

mike

My CTC-11 in the metal cabinet had its original legs and they were longer than that, as I recall. I suspect the Admiral's legs were similar. I eventually sold the TV, so I can't be more exact than that.

When I got the set, the legs were not attached -- just rolling around inside the cabinet. One of them had split around the screw and I was never motivated to fix it. I know it was a style of the times, but to my eye those massive cabinets look awkward standing on spindly legs. When the legs are made of wood you are just asking for trouble every time you move the set. Even with longer legs, the screen ends up pretty low to the ground. So I guess that is three reasons why I never felt like trying the legs :)

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Those legs are 5-1/4" long. I have a box of 7" legs, but they don't have the gold ferrule or the leveling pad. But as Phil mentioned - the longer you go the wigglier they get. I think the basic idea was to keep the cabinet up a few inches out of harms way, to fend off things like vacuum cleaner and toy strikes. :)

Also so the under chassis vents could get some air on carpeted floors.

I wonder if 5" ones would work where I have the set ? I will measure.

I'm getting along with this , Saturday I will measure the cathode ma , tweak the convergence where needed and tweak the sound , once its done I will try to post some higher quality photos, I did a little tweaking of the convergence and forgot how easy you can tear the skin on your fingers turning those controls.

anyone know if there's a modification that can be added to get rid of the retrace lines that come and go on copy guarded dvds ? its really not that important but it would be nice to know if someone figured it out , some black and white sets suffer the same thing some don't, if the dvd doesn't have it then it just plays without retrace lines that come and go and they aren't full lines like actually retrace lines .

mike

What you are describing is an effect of macrovision copy guard. You can buy boxes on ebay that can be connected between a DVD player (or VCR) and an external RF modulator that will remove the macrovision signal from the video.

I want to see if I can simplify this cathode current thing and test my own understanding at the same time. An electron tube in it's most common form is a triode or three section tube. I am using the triode for the sake of simplicity. There is a cathode circuit, a plate circuit, and a control grid circuit. So, given three sections there are three circuits involved in order to bias (provide a difference of potential or voltage) each of the sections.

So, if we were to want to measure the current flowing through any of these sections, we would have to break the circuit, and I don't think that it would matter where except within the tube its self which would be impossible. Once the circuit is broken, an amp meter would need to be connected in series. I must stress the fact that the meter must be IN SERIES, like part of one of the wires more or less, NOT parallel!!!

With all this being said, we should now be able to tell how much current is running through the circuit with no problem. So, in order to create a remote test port you would simply extend one of the wires feeding the cathode portion of the tube to an easily accessable location and create a method of easily breaking the wire and ineerting the meter. Then you want to be able to easily reverse the procedure and remove the meter, then provide a good re connection.

I am thinking that when designing this the best idea for me at least would be to install a glass fuse holder. Remove the fuse, perform the test, then reinsert the fuse. The fuse will provide protection from over-current so you won't need to worry about it anymore.

If you want to get really fancy, you could do the fuse holder AND a stand alone analog (or digital) milli-ampere meter. They can probably be found for sale on Ebay or possibly even some electronics supplier. A final thought for me is the use of an industrial motor over-current device, basically a breaker with a switch knob. Nice and reliable and you never buy fuses, but probably not cost effective.

So maybe this will help some as there has been some confusion on what to do here and it is a rather important issue from all I have ever read or heard. I don't have a schematic to elaborate on pin #s or any of that. I hope also that my take on this is correct.

The probable reason to measure the cathode current versus current at other elements is that adding a meter in the cathode circuit would be least likely to affect the circuit operation. With all of the other work done on one of these sets, temporarily unsoldering the cathode connection and using a couple of clip leads should not be too tricky, at least it was not for me.

I don't understand why manufactures didn't simply put a small value cathode resistor on the horizontal output. It would tend to drop the current a bit and add an element of safety, besides making it a simple matter to measure voltage drop across the resistor. Would that create linearity issues, or what am I missing?

never trust old electrolytics , I was running the set figured I'd finish up with the convergence , the picture shrunk and I shut it off , I was thinking something got in the set and was shorting , nothing , turned it back on , after a minute it shrunk and the breaker popped , I then poked around to see if any wires were messed up , I checked the power rectifiers and one was shot , I then checked the old electrolytic and it was hot , must have taken the power rectifier out , so even 15 minutes later it was warm , so now to replace it and the rectifier.

earlier I tried the cathode and I couldn't get readings on the meter , the set should have produced a picture and it didn't ,I will try again with the 10 amp input of the meter but if that doesn't work I don't have anything to check the cathode.
also checked the anode and it is running about 22k , I will recheck that once I get the set running again , I guess if its 22k and not 23 it will be ok , if it runs under 22k is that harder on anything ?.

mike

...earlier I tried the cathode and I couldn't get readings on the meter , the set should have produced a picture and it didn't ,I will try again with the 10 amp input of the meter but if that doesn't work I don't have anything to check the cathode.
Doesn't your meter have a lower range, e.g., 500 ma (1/2 amp)?

what if i was to put a resistor 1 ohm or less between the cathode and ground , I could measure the ma that way , I have .39 ohm 10 watt resistors wasting away I could add to try it

mike

Is your meter a digital readout or an old fashioned needle type readout? DMMs tend freakout and give nonsense readings when fed the high frequency non-sinusoidal current pulses of a HO Tube cathode. If you don't have an analog meeter Radio Shack has a relatively cheap one that I've found to work decently in measuring cathode current in these sets.

digital meter , I don't have any analog or a vtm

Well I put a 1n4007 in and it seems ok , also put a replacement for the electrolytic, I did accidently break the tip off the circuit breaker and changed it but the one I put in is rated at 1.75 , the one that was in it was 5amp , will the 1.75 be ok or will it trip ? I calculated the watts divided by volts and got 2.6 , the set is 310 watts , I tried a couple times a start up and it came on ok with the 1.75 , I even tried turning a set on one the same line to see if the momentary surge would cause anything , I almost plugged the vaccum in to see if that surge would do anything but didn't, so will it run and trip after a while because it is too low ?
now to try to get the ma measured on the cathode , get the sound tuned up a little and take some pics to post.

mike

I tried to get a cathode ma reading using a .39 ohm resistor between the cathode and ground , the set came on but I still got no readings on the meter , so I decided to remove the .47 capacitor to see what it would do then I got readings , so I removed the resistor and just hooked the meter up between the cathode and ground , I was getting 220 to 222 ma and thought that's a little high , so I turned the horz lin till I got to 200ma , the sams instructions say no higher then 210ma and the schematic says 200ma , so I put it to 200ma , it will drift a little to 201 or 202 and sometimes to 199 but mostly hangs at 200 , it does shoot up to about 225 or so on start up but quickly drops to 200ma, the fly is just luke warm so it is not running as hot as it was , the anode is 22kv area with very little change when you turn the brightness up or down , so looks like its running ok , I will know better when I adjust the vert height and lin for a more uniform circle , my only fear is what if the lin is off and the only way to correct it so it is more uniform is to increase the ma ? I wont know till I do more with it on Thursday , now I just have to tweak the sound to get rid of a little buzzing and it looks like it is going to be ready for viewing.

As a rule of thumb the lowest you can get the horizontal current without objectionably affecting the horizontal linearity is usually the safest setting for the fly to run at, though it should probably be fine as you have it now.

Well I got it up and running , fixed the sound issues , convergence is as close as it will get , it could use a degaussing but I don't have one , I will try to find a junk tv and take it out and use it to wave around the screen and slowly pull back , I did do the wire to the chassis from the cathode for future readings, the record player fan is a good idea , its quiet and keeps air moving inside even though its not rapid like a cooling fan but that would make noise.

I will post pictures as soon as I get them taken .

here are the pics , the colors look better in person , I do have an issue maybe someone knows what to do , when fade to black the picture gets bright , also when for example and explosion in a scne in voyage happens the flas of the explosion causes the image to go darker for a second while the flash of the explosion occurs , is this the video out tube ? I played with agc and it didn't seem to make a change.

mike

Looks good ! As for the brightness and explosions, There is a lot said here about sets with and without DC restoration to the picture tube biasing. It effects light and dark pictures, where they tend to drift off where they should be.... I can't say I have seen it so you should look to someone who has seen it.... But it's an idea, and some sets without DC restoration have strange brightness issues...

Could even be HV regulation issues..

perhaps I need to turn the hv up ? the contrast level changes depending on the scene or what is in the scene , it will look normal then scene change it will wash out and go back to normal when the scene changes again , just watched an episode of bonanza , was going to take multiple pictures but attery on phone died but was able to get one of the peacock , when it fades up its washed out , you can also see a ghost and a smear that runs across the screen , when the gong goes off and it is faded up the image goes black and the ghost is not visible, the blacks are black until fade then it becomes grey and washed out , only tube not changed in the set is the video 12BY7 I think is the number , anyway anyone know whats up? not enough agc ? hv too low ?
oh yeag have to tweak the red convergence just a little but that's not the issue here , the only way it looks and acts somewhat right is if you tune it back to where there is no color and I'm pretty certain everything is uniform at this point , try if tubes even though I put nos tubes in that test ok ?

Looks good ! As for the brightness and explosions, There is a lot said here about sets with and without DC restoration to the picture tube biasing. It effects light and dark pictures, where they tend to drift off where they should be.... I can't say I have seen it so you should look to someone who has seen it.... But it's an idea, and some sets without DC restoration have strange brightness issues...

Could even be HV regulation issues..

The only tube color sets I know of that lacked DC restoration were GE sets.

It is more likely that HV regulation is your problem. If the picture shrinks horizontally and or vertically (ie. blooming occurs) during the changes in scene brightness that is a dead giveaway that HV regulation is not working correctly.

As Username1 mentioned, it very much sounds like poor DC restoration to me. I have a CTC-16 with pretty good DC restoration, and a CTC-16X that is rather lousy at it. Since I cannot see any major difference between the circuits of the two sets, I have figured that it may be something that can be adjusted to work better, perhaps with just the right amount of AGC, CRT bias, and setup of the three guns. Or, maybe swapping tubes would help? This is a "someday" project for me. My CTC-16X HV regulation seems fine, for what that is worth, and its DC restoration is not very good at all.

the vertical and horizontal do not change , there is no blooming with brightness or contrast turned up and down , there has to be something not working right , I don't think it was doing this previously , so I will try swapping tubes , play with the agc , I might even turn the hv up so it is 23kv instead of what it currently running 22kv , I didn't do anything with the if board except I think I checked the orange or brown drop that was on that board , since it is shielded and tougher to get to I didn't do much to like check resistors it but maybe that's where the problem is ?
is that ghost an indication of the issue ?

mike

changed the 6aw8 and it made a little difference , changed the agc and it made a little difference , the 12by7 is weak , my subs are weak or have grid/gas issues , I will try a brightener but it seems like a waste since all the guns go up high on the tester , the green being the lower of the three but none show low emissions , no gas or shorts .

I put the brightener on and as I thought it made no difference , I did rebalance the screen controls and noticed something very weird , if you turn them all down it is supposed to have a dark screen , well turned all the way down I'm getting a green line no mater where I turn the control , turning it just increases the green brilliance of the green , so what I did was balanced the red blue and green and the colors are better now when they were before , another weird if I turn up the green drive I get a little more contrast in the image.

I guess I will go over the if/video board and see what I come up with , the changing isn't as bad as it was before from scene to scene , perhaps it was the agc but it still acts like dc restoration is not right and the ghost is still present , perhaps the delay line?

With all three screen controls down you should not have the green line. If there is a crt bias control you may need to turn it down until the green line goes away, then adjust all the screen controls. There may also be a resistor out of tolerance in the circuits biasing the green gun. Another curious thing is the drive controls. If I remember correctly most sets only had two drive controls. You start with them at max and reduce whichever is needed to eliminate color shading in the dark areas of the picture. End result should be a B&W picture with no color shading in the light or dark portions of the picture throuought the brightness range. If with the crt bias turned down you cant get a line with the screen control, leave that control up and turn the bias up until you get the line.

I've gone over the resistors , checked coils and other things , the delay line shows resistance , not sure if it is right I will hae to see if it says in the sams what it should read, only thing I found was a 56 ohm resistor that was 90 ohms , changed it even though it doesn't sound like something that was too far off, also changed a cap just to be sure , perhaps the video out tube is the cause , it is weak , a nos one is on the way, only other thing is maybe one of the capacitors that look like resistors maybe one is no good.

does anyone know what the resistance should be on the delay line ? theres nothing on the schematic and nothing in the parts list, it could cause the ghost and dc issue couldn't it ?

One way to test the delay line is to turn the color down and bypass the delay line with a wire. If the ghosting goes away with it bypassed then you've found the problem.

could I bypass it by just jumping the two ends together or does one end have to be disconnected when jumping it ?

thanks for the tip

boy this conversation seems all to real for me as i have a 63 silvertone with the ctc12 clone and i still have simillar problems with contrast issues changing on scene changes and some ghosting and also a bar that runs across the screen and moves alittle up and down on scene changes and the back ground colors with the bar present on a dark screen is darker on the bottom of the bar and lighter on the top of the bar . so i know what your going through here as i still didnt fine out whats going on with my set. so maybe ill sit on the side lines and maybe ill learn something new here from others that know more then me, lol,lol.....

I haven't read the whole thread, but it could be a luma issue. Have you replaced the bypass cap on the contrast control? It's in the cathode circuit of the 3rd video tube, if it's not working correctly it can cause the bias on that tube to drift making scenes vary in apparent intensity- reality is you've lost degeneration on that tube to some degree.

I haven't read the whole thread, but it could be a luma issue. Have you replaced the bypass cap on the contrast control? It's in the cathode circuit of the 3rd video tube, if it's not working correctly it can cause the bias on that tube to drift making scenes vary in apparent intensity- reality is you've lost degeneration on that tube to some degree.

would that cap possibly be a 0.1 or .22 ? or the 2- 390 caps because this may be something that is not right on my set as well.:scratch2:

No, it's an electrolytic cap. RCA service sheet has it as C124D, so it's likely a section of a multi-section can. Scroll down here, and look at the cathode of V708.

http://boxcarcabin.com/rcaschematics.html

i know my eyes are getting bad but i cant seem to find v708 in that schematic, is it infact there ?

It's your 3rd video tube, the 12BY7...

If you can't find it, click the link I posted and hold Ctrl while punching the minus key to shrink the page down.

I've replaced a couple film caps even though they are not leaky and might replace a couple others to see if there is a change , sad thing is it just happened , wasn't like this when I first got it running , I replaced all the electrolytics , also got a good 12BY7 , my previous had very low emissions so I'm hoping it too wlll correct things or maybe was the culpret.

I still wonder should I check all those resistor looking capacitors on the if board or at least the ones near the 6AW8 ? if yes and one is bad a mica cap will work there as long as it is the same picofarads value ?

I really want to put the thing back together and watch it

mike

Well the new 12BY7 helped a little but it still has the ghost issue and a smearing in white from the ghosting almost looks like ice in the white objects , the ghosting doesn't change when the tuner is adjusted but the smear caused by the ghost changes when tuned back too far and the color wont work ( pictures are to show ghosts and the smear and the changing of the smear ) get no color i , I jumped the delay line and saw no change or no effect , I guess you have to disconnect one end , I accidently disconnected the ground to the delay line , things looked odd and there was no brightness control , I found the cause of the bright green line when in service mode - too much kine bias.
I also checked the hot cathode with a .47 cap hooked to each end of the meter wires, I see 190 ma

mike

just alittle to add here, maybe a cap or resistor within the yoke as i had a simillar problem with a motorola and it was a resistor that was bad and thinking it may have been something with the fly i had changed it but didnt help. my silvertone has that ghost like image on some scenes but not all and i have a hunch it may be fly related as i cannot get a perfect focus because the focus voltage is alittle low and the focus coil had heated up at some point and i think it may have done little damage to the fly in some way. but we keep on keepin on....

focus is fine , no overheating of the focus control or fly , perhaps the if needs alignment or one or more of those resistor looking capacitors on the if board is at fault ?
be a real pain to pull them to check them

mike

well when i had some issues with sets i would use the stick on those cans and mark where i started and turn them one by one to see if i got an improvement and if not i would return it back where it was. i have had luck doing this in the past as one may be off just a bit . but if you do this remember to mark where you start first to put it back if you have to. but if the problem is corrected then leave it. just to avoid a whole alighnment procedure.

if you disconnect the delay line and jump it directly you get weak sync , no color , and its is jittery , I then tried a 2 ohm resistor and a 40 ohm resistor hooked to the delay line to see if the ghost and ice changed, it didn't , so my guess is the if section may need a tune up or maybe theres a cap or resistor in the yoke that's not right , or one of those capacitors that look like a resistor is at fault , I decided to give up and use it as is , its not unwatchable butit would be nice to have it a tad better , the cathode current on the horz out is 200ma , I had to turn the hv up all the way because if you don't the horz gets too skinny , focus is effected and circles are not circles , the anode is running 22kv and with brightness down around 22.5kv , the fly is not getting hot or warm, the convergence is very good , it does show some red around objects but that's with the color on , if you turn off the color they are gone so its not convergence , the red around objects will go away if you tune back but then the image is not as clear and you have to crank the color control high to get colors , again this suggests if tune up might benefit the set , can't complain about it because the colors are right and the image pretty sharp.
oh yeah I tried the stick idea and was careful, it made no change to the ghost , there is one that wont turn , its frozen , not sure which it is without looking at the schematic , just thought I'd add that

I also checked the hot cathode with a .47 cap hooked to each end of the meter wires, I see 190 ma

mike

So, is this the final verdict on checking that current. I'm curious because I am getting ready to put my new horizontal linearity coil in my Zenith and I want to measure the cathode current. I have never read about putting a cap on each meter lead.

.47 across the leads.

TJ and Timmy:

Are you talking about an analog or digital meter?

If analog (mechanical movement), no cap whatsoever is needed.

If digital (and I have never attempted to use a digital milliameter in that application AND WOULD NEVER), put as large a cap as possible across it, preferably several thousand mf.
This is because the waveform is complex and spikey and the meter will go nuts on that unfiltered waveform.
Considering that the meter presents a very low circuit impedance, a very large capacitance would be needed to attempt to smooth it. Even then i would not trust it.

Lacking an analog meter, i would use a #44 light bulb to accurately 'dip' the cathode current (as discussed in another thread).

with or without a .47 capacitor across the leads my digital multimeter is not erratic and shows a reading , I have it at 200ma and as it runs you may see it say 199 for a minute then back to 200 and while running it may show 199 again but eventually will show 200ma , the capacitor across the leads is mentioned in the procedure in the sams how to test the cathode current, and I should metion the meter has that separate 10a for the red lead to plug into , that is how it is used to measure ma , if one tries with it in the standard input that reads ohms and volts it will not give a proper reading.

I never saw an issue reading HOT current either, with or without the cap. I insert a 10-ohm resistor now though, and measure voltage instead of current.

Just the way it was worded sounded like one connected in series with each lead as opposed to one in parallel with the two leads. I think I will go with the mighty Simpson analog meter. No real reason; I just like analog meters, but I firmly believe that you could do the job with a digital meter and get a rock steady reading.

:tresbon:...I think I will go with the mighty Simpson analog meter. No real reason; I just like analog meters,..
You're speakin' of the Simpson 260, right? That's the only meter i ever used for general servicing for 30+ years (except for the rare occasion when a VTVM was needed for probing some high impedance circuit).
...but I firmly believe that you could do the job with a digital meter and get a rock steady reading.
You might be able to run red lights and stop signs for a while, too.:) I would never use a digital (don't even own one) for anything but pure DC, clean sinewave AC, or ohms.

and yes i was talking about the cap with a digital vom. and of course i have yet another problem with this ctc12 clone, in the service mode and all the drives down counter clock i have a blue line across the screen and the crt bias down as well, counter clock. any ideas, maybe a bad bias pot , i dont know but would like an idea befor pulling the chassis. although i do use an analog meter now for cathode current

I'm just guessing but check the bias pot , any associated resistors , also check the blue drive and associated resistors and then if all else checks try the blue screen , also if that fails make sure the crt socket has clean contacts but start with the bias and work from there , if old coot has better ideas from experience I'm sure he will pipe in.

old coot any idea whats causing the ghost in my set ?
mike

:tresbon:
You're speakin' of the Simpson 260, right? That's the only meter i ever used for general servicing for 30+ years (except for the rare occasion when a VTVM was needed for probing some high impedance circuit).

You might be able to run red lights and stop signs for a while, too.:) I would never use a digital (don't even own one) for anything but pure DC, clean sinewave AC, or ohms.

I like the way you think! :thmbsp:

I would like to learn more about exactly what a VTVM can do that no others can do, or do as well. I have a Simpson VTVM and a huge bench model Hickok.

old coot any idea whats causing the ghost in my set ?
mike
No idea. But for a start, i'd check all the peaking coils 'downstream' from the video detector thru the video output. They're little single-winding coils that normally measure just a few ohms or less. You don't have to disconnect them to measure, since the ohms are so low.

TJ:
A VTVM's main advantage is its very high input impedance. It doesn't impose near as high of a load on a high impedance circuit as the VOM does, thus minimizing loading error. An example of such a circuit is the AVC (automatic volume control) buss in an AM radio.

I did check the peaking coils and rechecked , they all measure low ohms , nothing above 10 ohms.

did you check any of the caps or resistors within the yoke? may be worth a try.

What would the yoke have to do with a ghost or 'ice' in the video?:saywhat:

because i had a simillar problem with a motorola 23 inch color and it turned out to be a resistor. just throwing that out there being no one seems to be able to narrow down this problem he has with that set. there could be a convergence issue there are caps and resistors there as well.

Timmy I think old coot could answer this - the convergence is lining up the red blue and green , this issue seems to be video or IF related and looks like its in the black and white portion of the image , am I right or should I look at convergence ? my next step since I've checked everything else would be to check the video areas and those resistor looking capacitors , I don't know what else to check , they are all low values like 10pf 20pf 6pf etc

mike

...the convergence is lining up the red blue and green , this issue seems to be video or IF related and looks like its in the black and white portion of the image , am I right or should I look at convergence ?
From the pics you posted of the "NBC" symbol display, the "ice" problem appears to be in the luma (video) or video IF chain. Definitely not convergence or yoke related.
Assuming the problem's already determined to be not tube related, troubleshooting just about demands a signal generator (like the B&K 1076 Analyst). Working backward from the vid out stage, inject signal stage by stage until the problem's isolated.