Rca ctc-5 - Page 4 - Videokarma.org TV - Video

kvflyer · #1 10-02-2012, 04:36 PM

Sounds good. We'll be 'a watching...

DaveWM · #2 10-02-2012, 04:46 PM

the few caps I did not change were the domino types, there was at least one large value 1000pf on the horz board. I figured I would leave them be until I test it and see if there is an issue. This thing sure has a LOT of paper caps.

A quick pass did not turn up any faulty resistors. I did have an open fuse the .75amp on the top. I did not have the correct fuse type, so I rigged up a in line fuse holder that uses the blown fuse as a plug, and lets me use the more common stye. Just a temp fix until I get the correct fuse type. There is a B+ fuse, a HOT cathode fuse, and I am not sure what this one is for its a bit confusing on the schematic, seems like its tied into the yoke/vert out/damper circuit.

DaveWM · #3 10-02-2012, 05:37 PM

so whats the deal with the yoke plastic?, I seem to recall this being a problem and there being some easy fixes using common plastic parts. Mine is turning into a white mess.

DaveWM · #4 10-02-2012, 10:25 PM

one shorted 6EA8 AGC and sync amp, Schematic shows a 6U8 a quick check shows that as a sub
weak 6LF8 1st video and noise inverter, schematic shows a 6AW8 a quick check shows that as a sub
getting tired still need to check the chroma and video amp, the rest look ok.

wkand · #5 10-07-2012, 01:15 AM

Hi Dave:

Where did you get the skinny electrolytic caps you used to replace the former FP cans? I've never seen high volt electrolytic caps like that before.

Charlie · #6 10-03-2012, 07:09 AM

Yeah that yoke plastic sucks, doesn't it?! I've got a few sets that have that issue... or simply a lack of plastic to hold it all together in there. I notice that Motorolas of that time period seem to always have this issue (as well as Motorola knobs).

Bob has section covering this on his site at http://antiquetvguy.com/Web%20Pages/...okeCovers.html

DaveWM · #7 10-03-2012, 07:06 PM

all tubes checked on the chassis, did not check the tuner tubes, and did not replace any paper caps on the tuner (I think there is one). So hopefully I will be able to do that tomorrow, then maybe Sat I can give it a try

I replaced the one 6EA8 with the slight short and a 6LF8 that was shorted a bit harder.

DaveWM · #8 10-06-2012, 05:14 PM

got raster, then pic and audio, but the pic looks like its got an agc issue or a sync sep issue, (vert and horz sync are soft). HV is right around 20kv but that is thru a 100ft cord AND a isolation trans that can barely handle 3amps, so I am hoping at full line voltage it will be up a bit. I did not see if the HV adj did anything. the tuner has a paper cap so maybe that is an issue, I presume its an AGC filter cap. I will start by replacing that. I did not fiddle with the AGC pot so of course that could be it as well. If neither of those work out I will try a composite video feed. I need to back and review the AGC setup.

Its coming along...

DaveWM · #9 10-06-2012, 06:25 PM

hmmm I seem to recall cleaning the pots up front, so I bet I just need to reset the noise/agc, but too tired to fool with it any more, so back on it tomorrow.

DaveWM · #10 10-06-2012, 07:05 PM

AGC pot has no effect what so ever. So I think I will start with a simple AGC bias and see if that clears it up. If so I will dig into the AGC circuit. I just hope its not a feed back pulse from the fly back that is missing.

mstaton · #11 10-07-2012, 04:44 PM

Convergence is a real pain in the ass on those sets. Be prepared to spend an entire evening doing it. it will never be perfect. Just get it as good as you can and leave it. Those DC pots will need to work to get the convergence right or your efforts will be futile. Don't turn the coils all the way in otherwise you may never get them to come back out without removing the chassis. Been there, done that.

mstaton · #12 10-07-2012, 05:51 PM

Looks decent. Much better than mine but mine needs a full alignment and is a Super.

DaveWM · #13 10-07-2012, 05:58 PM

its a CTC-5N, I am using a super cabinet which had the good CRT in it.

DaveWM · #14 10-07-2012, 06:02 PM

I am also at the extreme end of the vert hold to lock. I did not replace all the caps, there were some orange drops in there in the feed back circuit, I left them. I will try a new tube JIC its getting gassy or weak, but if that does not do it I will recap those old caps and check the resistors in the vert hold circuit and the pot as well.

DaveWM · #15 10-07-2012, 09:41 PM

oh and what is the function of the metal disc on the back of the yoke plastic anyway?

went back and re reads Bobs article, magnetic shield, I presume from the yoke to the convergence area.