i just picked up a yamaha ps-3 for $5, it turns on ok and works when plugged into an external speaker, but no sound is coming out of the inbuilt speaker, i have checked the connections and it all seems ok. what could be the trouble?
Since the audio out jack probably switches off the speaker when engaged, check to make sure there are no shorts around or in the jack itself. You may even try desoldering it.
Tried a new speaker? I've had plenty of toys not play any sound and then I put a new speaker on it and it'll work fine.
If you saw the speaker you would understand how that isnt a possibility.
i still have not been able to figure out what is wrong with it. i have also just noticed that on a couple of instrument settings (harpsichord), the bottom few keys do not work below 50% volume.