Hello Syntaur forum. Recently got an old Yamaha CVP-50. Everything works, but it has an intermittent problem where the sound stops and all keys and buttons cease to work. When this happens, the power stays on (LED numeric display and other lights stay lit), you just can’t play or change settings. I can find no rhyme or reason as to what makes the issue occur. Sometimes you can be playing for 30 minutes and it doesn’t happen at all, other times it can happen within seconds of turning the piano on. The instrument sounds great otherwise and I’d hate to throw it away. I’m not completely unfamiliar with electronics (although I usually work on tube stuff), but I wouldn’t even know whether this is a hardware or software problem. I appreciate any input anyone might have.
It’s worth checking the power supply on these old keyboards.
Look for any scorching or leaking caps.
Check the power rails to see if they’re in spec.
Get the service manual for the CVP-50 too.
Let us know how you get on
I checked the power supply over and it looks ok. I found the service manual and the instructions for the test program (image below). The tests seemed to check out with the following exceptions:
Ao: Indicated a RAM error.
E1: Did not work.
After running the RAM check test it almost seems like things are worse now, as the autoplay tracks seem to freeze for a sec before picking up again.
It’s likely the RAM chips are faulty and will need to be replaced.
Not sure what they are in the CVP-50, but Aliexpress sell loads of stuff for repairs.