Hitachi turns itself off

Here we go again. Hitachi model #50EX10B. Replaced the green CRT. Works

fine, just have serious mis-convergence that I'm working on. Anyway, now the darn thing tuns itself off after playing for about 20 minutes. Hit power button and hear relay click. Wait about 30 seconds, hit power

button again and set comes back on. About 3-5 minutes later, goes though the same sequence. I'm guessing it's heat related? Just not sure

where to start looking. Any ideas? Thanks group.

No idea's? Anyone please?

Guess answer...coolant spill?

Tom

I don't know this particular set but I repaired a Zenith in years past that had a problem of turning itself on at all hours of the night. Problem was silver migration on the the pcb (in the TV) that receives the transmission from the remote control. Solved problem by cleaning between the traces with a pencil eraser.

Maybe your set th> Here we go again. Hitachi model #50EX10B. Replaced the green CRT. Works

I wish. I replaced the green CRT with a new one. After this, the set powered up OK, but convergence was bad, especially the blue. Adjusted the static, then dynamic (fun) convergence, and picture is close to accepable, but not quite. Anyhow, like I said, once powered on initially, it stays on longer prior to shutdown than after shutdown and powered back up. One more clue, if I don't leave the set shut down for at least 20-30 seconds, and power it up again, the picture seems to display interference like bad reception, but will clear itself up after a minute or so, then will shut back down as said after a few minutes. Prior to changing the CRT, when hitting the power button, the set would try to power up (red led come on), then shut down. Only way to power back up was to unplug it, plug back in, and turn on. The set would then stay powered up. Of course it got to where it wouldn't power back up - fracture in green CRT neck, causing shut down, and blowing fuses, Hots's, etc. There seems to be a definite time period I have to wait before the set will power back up - 10-20 seconds. Does this sound like a possible capacitor problem, leaky diode? I tried freeze spraying everything, but nothing found yet. Thanks for the replies to all. Still hoping for one hot tip.

What is the number of the regulator in that set..

kip

I would look into the deflection and convergence circuits, seriously. Do you think that green CRT cracked all by itself? Do you think there is no logical reason for protection circuits to be kicking in after some part of the convergence heats up beyond safe limits?

Yes I do, but I am a beginner in repair. I have been told by a friend (TV repair man) that this is not uncommon in older TV's for a hair line fracture to develop. Maybe from sub-standard production, etc? Anyway, I am still fiddling with the convergence adjustments, likely because I am avoiding the shut down issue. If the set was shutting down by protection circuits, would it power back up after a short time period without unplugging the set? Thanks for the reply.

Are you convinced the degauss is turning off properly (you mentioned a click)? You might try disabling the degauss circuit, to see if there is any change.