RCA Shuts off after 1/2 hour

[oakdust]

I have a RCA with CTC203CA6 Chassis. I replaced the flyback due to arching from a pinhole in the side of it. After replacing it the set will run about 1/2 hour and shut off. Will turn back on but shuts of right away. Once it cools down it will run for about 1/2 hour again. I am looking for a bad capacitor or something more complicated. I checked the caps before replacing the flyback and ESR was good. Haven't tried tracing with a hair dryer yet,

 

[shrtrnd]

Not familiar with this particular chassis. I'd look at power transistor close to flyback. They're usually bolted onto a heat sink close to the flyback. My guess is damaged with your flyback problem. It'll work till it warms up, then cause problems. If you've got a can of freeze spray, you can check by letting set warm up till it shuts down, then hit the power transistor with the freeze spray and see if the set immediately turns back on. If that's it, you've found the problem. Good luck.
PS. If that's not the one, hit the other power semiconductors with the freeze spray, you've got a temperature problem where a semiconductor is not working when it gets to temperature. The freeze spray will find it for you.

 

[oakdust]

So far I have tried a heat gun and could not get it shut down. But, I did have a bunch of some type of sealer at the high voltage input on the pic tube, forgot to clean it off.
So now I've cleaned it and so far the set has been running for 34 minutes. So it's just wait and see. I suspect the sealer was not allowing the the clip to seat right on the picture tube. I'll let ya know what happens!