A while back I got an old 1991 yamaha psr-530 and it was in great condition. Eventually a problem started happening where all of the Ds and Gs stopped working making it pretty much impossible to play. after a while I removed the speakers so that I could use them is something else and when a friend came over and tried it out, BAM it worked fine. Of course, I had to plug it into other speakers with the headphone port. Later, I put the speakers back in to see if it would work. I didn't even plug them into the board I just put them in the case and it stopped working again. This would all be fine considering its working fine until recently the lowest G stopped working.

I disassembled the keyboard again, this time to completely dismantle it to the point to where I could clean the keys. I cleaned the keys and the key button pad things and put it back together. I must have put the pads in the wrong order because this time the lowest G worked but the middle G did not.

 

There can be lots of reasons why D & G stopped working. At the first occurrence it seemed to happen across the keyboard I would have suspected a failed circuit, the part that generates the tones. Obviously there are a number of octaves that must be controlled by some circuitry I'd look for the common point where all those keys (the D's and the G's, each likely being a different circuit) and look for a common solder joint that may have failed. Since the G's came back, all but one, I would think the first scenario would be inaccurate. Then after cleaning the low G came back but the middle G went - you're right, something weird is going on. But probably not.

I don't know how the circuitry is designed, but at this point I would start suspecting the tone generator as being faulty. It may be a single chip for each note or it may be a multiplexed chip for each note in the highest octave, leaving the low and the middle octaves to be reproduced via divider network. But all of this is guesswork on my part.

The most confusing part is that you cleaned a switch or sensor pad and changed the characteristics of the failure. I have a Cassio keyboard that I bang on every now and then. I can set the keys to respond according to the amount of pressure I tap the key OR to simply act like an on-off keypad. I would suspect your Yamaha has the touch sensitive keypads. Not sure if cleaning them is even possible - but again, I don't know.

If you are so inclined, what would happen if you swapped a C touch pad with a D touch pad? Not sure that's a wise thing to try, but honestly I don't see why changing touch pads would make a difference. If you lose all the C's then it may be safe to conclude the issue has to do with the touch pads themselves. And when something is failing it may fail intermittently, allowing it to work unexpectedly at some odd time coincidental to your messing with speakers or not. Just because something weird is presenting itself - don't assume that's part of the failure mode. It could just seem that today middle G works because the mail came late and tomorrow if the mail arrives early middle G won't work. The arrival of mail has nothing to do with your keyboard. Just coincidental.

 

There can be lots of reasons why D & G stopped working. At the first occurrence it seemed to happen across the keyboard I would have suspected a failed circuit, the part that generates the tones. Obviously there are a number of octaves that must be controlled by some circuitry I'd look for the common point where all those keys (the D's and the G's, each likely being a different circuit) and look for a common solder joint that may have failed. Since the G's came back, all but one, I would think the first scenario would be inaccurate. Then after cleaning the low G came back but the middle G went - you're right, something weird is going on. But probably not.

I don't know how the circuitry is designed, but at this point I would start suspecting the tone generator as being faulty. It may be a single chip for each note or it may be a multiplexed chip for each note in the highest octave, leaving the low and the middle octaves to be reproduced via divider network. But all of this is guesswork on my part.

The most confusing part is that you cleaned a switch or sensor pad and changed the characteristics of the failure. I have a Cassio keyboard that I bang on every now and then. I can set the keys to respond according to the amount of pressure I tap the key OR to simply act like an on-off keypad. I would suspect your Yamaha has the touch sensitive keypads. Not sure if cleaning them is even possible - but again, I don't know.

If you are so inclined, what would happen if you swapped a C touch pad with a D touch pad? Not sure that's a wise thing to try, but honestly I don't see why changing touch pads would make a difference. If you lose all the C's then it may be safe to conclude the issue has to do with the touch pads themselves. And when something is failing it may fail intermittently, allowing it to work unexpectedly at some odd time coincidental to your messing with speakers or not. Just because something weird is presenting itself - don't assume that's part of the failure mode. It could just seem that today middle G works because the mail came late and tomorrow if the mail arrives early middle G won't work. The arrival of mail has nothing to do with your keyboard. Just coincidental.

I was pretty sure that the problem was somehow connected to the speakers because I tested it twice and I thought it might be something about the magnets. but that may be the case that it was just coincidence. it could have been as you said the connection point between the button boards and the main board. but the first time I did not even touch that part, just the speakers. the second time I removed the button board and took out all the pads and dusted out all the dust out of the keys. each velocity sensitive button pad is separated into octaves except the bottom note with is a single pad. so I may have switched the bottom octave pad for the middle is my thought.

As for why all of those notes stopped working I don't have any clue. I will take apart the keyboard and send some photos soon.

 

I opened it up again and put in the speakers. You where right, probably just a coincidence.
all the keys work still except the middle G. nothing changed with the speakers.

as you can see, highlighted in blue, the note was was not working before I cleaned the keys. highlighted in red, the key that is currently not working.


Here is the keyboard opened up. I hope my cameras quality will do.