This is one of the more interesting jobs I’ve had. The Q-Chord Omnichord which is actually made by the Suzuki Corporation. The current owner of this one took a gamble on buying it in a broken state. It looked as if a previous owner had not noticed all the screws that hold the covers together and had tried to prise it apart with a screwdriver. The PCB inside had a big crack in it and the DC power input jack was mashed. I did manage to get it all working in the end though you had to press quite hard on some of the chord buttons on one row to get them to sound. They use a conductive rubber pad under the button sheet to make contact. I cleaned the pads as best I could and guessed that with use they might improve. This model has a rhythm section. The plinky plonky tune (in a key to match the chord button currently playing) that is created by touching the touch sensitive strip to the right is quite delightful.
Here is a photo of another one I have just been working on: The Omnichord OM-84.