Yamaha YPG-235 Single Key Dead - cleaning contact didn't work

Synth Repair
1

The second-highest D key on my Yamaha YPG-235 has stopped working. I have taken apart the keyboard and cleaned the contact - still no sound.

Will replacing the entire upper contact board (Key contact board, 43-note (High), Yamaha - Syntaur) likely solve my issue or is the issue on some other board?

How can I isolate where the fault is? I am comfortable with a multi-meter and checking if two spots are connected/conducting - I just don’t know which two spots to put my probes. Is it okay to put a probe directly on the contact part of the board (where the rubber hits the board) - I don’t want to scratch or break the contact point.

Thanks for your help.

2

Have you checked the diode for the key and made sure the tracks shows continuity?

3

Should I remove the contact board to check those things? Where exactly is the diode?

Re: continuity, I have checked some things but not entirely sure if the right things. So far everything has been connected.

4

Yes, I’d remove the contact board so it’s easier to do.
Have you got the service manual for your keyboard? That will show you the schematic for the contact board.