Our Yamaha keyboard PSR-230 has been stored for some years in the attic and now that my grandson is into music playing we got it down only to find that it does not produce any sound from the speakers any more and it was a-OK when stored. When running the DEMO we can see the music playing on the LED's above the key's but in silence. I managed to find a service doc and see that I have 0 volts at pin 5 (STBY)from the power amplifier (LA4705) module.The ON signal is supposed to be a "PCo" from IC100 (GEW10) pin 18 & 55. I don't see any electrolytic capacitors with a "dome" head in the path as I sort of would suspect that this could happen after the long time not powering it up. I find it hard to believe that the signal from pins 18 and 55 from IC100 would go wrong and I can only measure with a scope on connectors CN400 and CN911 that it is 0 volts. As the IC100 is on the underside of the PCB I can not measure directly on the pins of the IC. Anny suggestion will be highly apreciated. Cheers
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