I have a lovely fp-5 that I refurbished years ago. I replaced all of the pads and many of the keys and it played like a dream.
Unfortunately my cat knocked a potted plant and a bunch of sand in to the keys and now the sustain is always on. I’ve taken apart the piano and cleaned the innards out and yet the problem persists even when the pedal is unplugged.
I’m trying to figure out what parts I might need to replace to get my piano up and running again!
Wondering if the impact of the plant broke some electrical connection or component on a pc board. The sustain pedal is just a switch. Does the sustain pedal jack look ok?
The sustain function and the keybed are really two separate things. I’m with Mike. I think the cat deviously pushed the plant over, and it dumped sand in the keys as it hurtled toward terra firma. The pot itself hit the sustain pedal plug as it crashed into the keyboard, and the plug pried the sustain jack up from the PCB it is soldered to, just enough to break the circuit.
On Roland (and Yamaha) keyboards, the sustain circuit is normally closed. When the circuit is opened, notes sustain. So the pedal is a closed switch which opens when you press on the pedal. And if nothing is plugged into the jack, it is ‘normalled’ to be closed. The dropping pot broke that normalled connection, and now it sustains always.
That’s my theory, and I’m sticking to it. You may be able to repair it by resoldering if the solder connections got broken. But I’m guessing the jack itself is damaged and will need to be replaced. You’ll need to open the keyboard up to see any damage.