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Need some help with a tv

Its been a lonng time since I posted here last, anyways I have an old rca tube TV. More specifically an rca truflat crt. I started it up today and it displayed static and warmed up like normal but then it shut off and started making a chirping noise. Almost sound like the flyback is trying to start but then stopping. Does anyone have any knowledge of these type of sets before I tear into it. Most of my experience is with tube tech not solid state lol.


Thanks in advance, Ray -kd2jid
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Check if the LOPT transistor is short - the chirping is probably the PSU tripping out due to the overload, and trying to restart.

It's also quite possible that the LOPTX is faulty, that's a common cause for blowing the LOPT transistor.

Disconnect the LOPT transistor, and confirm it's S/C, and try the set without it - obviously it won't run, but it shouldn't chirp any more. Then connect an incandescent bulb (I used to use 60W 240V) across collector and emitter connections where the transistor was, and it should run fine at about half brightness. If you're on 120V?, then try a 30W bulb, which should be bright.

Assuming that all works OK, replace the transistor and try again - keep a close eye (and ear) on the LOPTX, as flashing over internally blows the transistor immediately.
 

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