Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
It would be a shame if parts were not available - but parts are available. The only question is, whether what is available matches what you need:
Syntaur was the first parts vendor that came to mind - but they seem to offer no Kawai parts (on their website anyway) except switches and IC chips.
(You can call their number and inquire: (###) ###-####)
Then there's the possibility (since searches otherwise have come up negative) of getting the right part # for the Kawai part you need first, then searching with that part # (a much more powerful technique than searching for any description phrase (and there are so many, etc. etc.) - and the part # may be gotten from a service manual:
scroll down until you see
Kawai PN80 Digital Piano Service Manual
and then click on the BUY NOW button to the left. (Note: I don't know this vendor.)