Dark Picture/Black Bars Across Screen - RCA CTC-44A Chassis - Videokarma.org TV - Video

joeseattle70 · #1 07-26-2009, 11:39 AM

Turned on my beloved 1971 RCA console tv this morning, and after a few minutes, screen started getting dark and solid black bars went across screen - almost like "black out". Turned off tv, let it rest, turned on - was fine, then within a few minutes, it happened again - whenever what component gets warm failed, it became evident again. Any idea what might cause this? Convergence board was re-done last year, so should be ok - could it be the tube or another transistor/capacitor on chassis? Turned off Auto Tint and AFT to see if it was those circuits and it had no effect on it. Also tried vert/horiz hold and had no effect either. Thanks for any ideas!!! Joe

radiotvnut · #2 07-26-2009, 12:38 PM

Sounds to me like a bad electrolytic cap in the power supply.

drh4683 · #3 07-26-2009, 03:28 PM

Yep, I agree, bad cap. with the back cover removed, turn the set on and wait until the black bars appear on the screen. Once you see the problem, unplug the set and feel the filter cans. Any that are warm or hot to the touch are bad. This doesn't always work though. The best way is to test them for leaks is with with a VOM set at low resistance from the cap to ground at each terminal. I use an ESR meter for all cap testing, even though the ESR meter can show improper "good" results if a cap is leaky. otherwise I use the VOM together with the ESR meter, which generally, you can pin down most cap problems without disconnecting them from the circuit.

joeseattle70 · #4 07-26-2009, 06:57 PM

I very much appreciate it. I'll check this out. Would you suggest changing out all caps or just affected one? Thank god it's a solid-state chassis - don't have to worry about all those pesky tubes!

radiotvnut · #5 07-26-2009, 11:18 PM

It would, of course, probably make the set more reliable if you changed all the electrolytics. However, the metal can style caps are more reliable than the cardboard caps and may well operate fine for another 40 years. I will tell you that if the culprit turns out to be a faulty section of a multi-section can; then, you'd do better to change the entire can. In my younger days of TV repair, I would often get lazy and replace only the bad section of a can. More times than not, the other section(s) would fail within a week or two and come back to bite me in the butt. With that in mind, I always replace the entire multi-section can even if only one section is bad.

Findm-Keepm · #6 07-28-2009, 07:41 PM

Anyone have a set of RCA service literature? I seem to recall an RCA "Goldenrod" (so named because the paper they were printed on was goldish orange) that mentioned the black bar problem on the CTC-40's and CTC-44's. Reckon I'll do sum diggin......

Cheers,

Findm-Keepm · #7 07-28-2009, 07:51 PM

Found what I was looking for - hope this in some way helps.

Cheers,

bgadow · #8 07-29-2009, 01:45 PM

Any interest out there in a nice set of RCA service lit? My friend at the TV shop has them, covering the 70s and maybe a little beyond. They don't interest me much, since most are solid state and space it tight. I won't let them get thrown away, though.

joeseattle70 · #9 08-06-2009, 08:16 PM

Thanks everyone! The entire video board needed to be overhauled. Once everything was re-set up, etc...I could not believe the difference!!!!!! WOW!!!! It had a great picture before, but you should see it now!! Of course I was a kid when the set was new, but I certainly never recall the picture being this sharp. Thank God for the solid state chassis - can just replace electronics as they go bad one transistor/capacitor at a time vs. whole boards on this new garbage they are selling for big bucks. Another save by the forum - thanks, guys!!