[Solved] Yamaha P95 keyboard help thread (no power)

Thread Starter


Joined Dec 6, 2021
I’m trying to do a good deed and help someone with this piano. It was given to me powering up but making no sound. I found 2 capacitors that seemed to be leaking (C122 and C408.) I replaced them but unfortunately the FFCs separated from the reinforcement and got a bit mangled. So I tried fixing them, but now I get no power at all - no LED when I push the button.

I‘d like to figure out how to diagnose this thing to figure out if it’s the cable and/or something else. I could just buy new cables from Mouser but I’m on an island and would prefer to just place one parts order if possible.

I‘m new at troubleshooting circuits, but I have built several guitar pedal kits and a few tube headphone amp kits. Fortunately or unfortunately the all worked right from completion so I didn’t get to troubleshoot much.

Some questions:
What does +5A and +5D mean? Is that AC and DC voltage?
what can I probe to verify power is making it to the switch and back?

schematics are in the manual with block diagrams, here:

Thank you SO MUCH for any guidance!