1979 Moog Polymoog Keyboard

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via this auction

This one was spotted and sent in via MATRIXSYNTH reader John Ryan. Note it is being sold for parts. You can find additional pics of the inside below.

"I picked this up at an estate sale, not knowing if it would work and also somewhat familiar with the complex design of it. The seller didn't have any info as to where it was stored, last used, etc.

It powers on, and the lights come on, but it does not produce any sounds. All of the preset buttons still seem to work except for number 4.

I did a few of the diagnostics that people recommend you do when getting a Polymoog, here's what I found:

I disconnected/reconnected all of the plug cables to the boards, and also took out and reseated all of the individual soundcards (there's one for each key).

I tested the resistance, for the 15+V, 15-, and 5+vols. There is some sort of short on the +15, and the short goes away when I disconnect the right hand circuit board, so it's pretty likely that's where the problem lies. I also tested the voltage for all three, and they were fine, in that regard.

Once I realized that it wasn't a working unit, I didn't go any further and didn't dismantle the keyboard, as restoring this is beyond my meager skills. All keys are intact and responsive to touch (meaning, they return to the top when you release them). The circuit boards seem pretty clean, as do all of the individual key cards.

There are no signs of any sort of bloated capacitors or anything that looks fried, and no strange smells or smoke when it is plugged in and on. Does not include the legs.