Left speaker not working on Yamaha CLP 300

by Jim
(Alliston, Ontario, Canada)

I have a Yamaha CLP 300. I have had this keyboard from brand new and it's about 30 years old. I've had zero problems with it through the years until 2 months ago; The left speaker stopped working. At someone's suggestion, I tried spraying some contact cleaner/lubricant into the volume slide opening and vigorously slid the button back and forth, still doesn't work. I called Yamaha and and independent repairman and they are hesitant to touch it because they aren't sure if parts are still available for this model. This keyboard has sentimental value and I would like to pass it on to my kids, but I don't want to pay extravagant repair/part fees. Does anyone have any experience or suggestions as to what I can do to fix it?