Yamaha SK-15 Cleanup

For EXEDO, Christine and I bought a Yamaha SK-15 string organ synth from 1981. It is a sturdy, well made instrument which worked pretty well out of the box for a well used (even dare we say vintage) instrument. Nonetheless, the knobs and sliders were very dirty and had a lot of dropouts. The master volume knob sent waves of deafening crackle through the amp when you turned it. One of the keys was intermittent. so I opened it up and gave everything a good cleaning. The top metal cover has a few screws holding it closed which, once removed along with the fader caps, allows the panel to hinge up and out of the way. The faders and knobs all got cleaned with isopropyl alcohol, the corner of a folded paper towel, and a little bit of deoxit fader lube. the faders were pretty easy to get into the fronts, once the felt dust cover (shown below) was removed.

 To clean the keybed, you have to remove a couple screws from the underside of the front edge, and the entire keys assembly tips upward. then you have to remove the white plastic things in this picture below to expose a conductive plastic strip with a rubber contact strip that lies under the keys themselves. The header connectors shown below need to be disconnected, as well as some grounding wires that connect the key assembly to the bottom of the case. In between the rubber strip and the conductive plastic (Sorry I didn't take any better pictures) I found a lot of dust and debris. After cleaning with IPA and re-assembling, no more key dropouts!

To hear this string/organ synth in action, you can listen to the EXEDO demo or else check out this youtube vid: