Quote:
Originally Posted by vidjoman
It's not good to just guess what to replace without doing proper fault finding and voltage checks.
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Exactly! I couldn't have put it better.
While it could be something to do with oil in the optical side it could also, and more likely, be due to an amplifier fault. If you don't know the service history (if any) of the amplifier, then there may well be leaking grid coupling capacitors ready to do some serious damage and these would cause exactly the fault that you have. However, I had this fault symptom with my B&H projector and the grid coupling capacitors had already been replaced by a previous user, but the output valves were (to use an American term) seriously 'red plating' and dragging the HT down after a short time of operation. The fault on this occasion was caused by the cathode bypass capacitor for the 'shared' cathode resistor going totally short circuit. This capacitor was in a block of three, with the other two being the reservoir and smoothing capacitor. Disconnecting this faulty capacitor section and fitting a new replacement in circuit cured the problem.
So a few things for you to investigate, but remember, proper fault finding and no guesswork, as it'll likely end in disaster!