I am working on the subject TV set and it's stuck in standby. Does anyone know where I can get the dead set troubleshooting guide that covers this chassis? This TV has a complex set of protection circuits! Thanks,
Marc
What do the +143V and the +15V supplies measure in standby? This is one of the simplest and most reliable Thompson chassis ever built. Nothing complex about it. Protection circuits usually activate after at least an
*attempt* to start.If the +143V is too high in standby (over 155V) replace the 2.2uf, 15uf, and 39uf or 47uf capacitors in the power supply front-end. If the +143V is o.k. in standby, but the +15V supply is less than 12V or so, replace CR4118. If the +143V supply is zero, your supply is not running, or is in over current protection. Check for a shorted HOT and associated components (Yoke return cap, pincushion diode and cap). If all seems good, and set makes no attempt to start, check for a tied-up keyscan. If you lack a 'scope, have no spare keyboard, and have the time, try removing the switches from the keyboard and using the remote to turn on via IR codes. Without me writing a book, check this stuff 1st, as it covers 90% of the problems this chassis has ever shown.
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