Moog Music Forum

I have two issues with my old Moog Prodigy v.1 with cv mod

1: Osc2 gets higher and higher in pitch the higher up you play on the keyboard. I have opened it up and turned the key scale trim pot. Osc1 is in perfect order!!!

2: sometimes , very seldom, the highest octave on The keyboard trigger a half note to high. If you press The same note again it switches to The correct. Only on The last upper octave C--->C

Something you can fix easily or leave it to a pro?

Best regards Janne
//Sweden

I have now figured one Thing out.

All works fine the first hour but then suddenly an electric buzz / noice is coming from inside. Not to the Audio out.

Then The upper octave goes out of tune (gets too high in pitch)

?????

Sounds for me as if there would be a temperature problem with the transistor array U3 (3046). This IC controls the octave "spreading / inclination" of oscillator 2. Try to replace it and / or resolder the pins (might be on socket).

All your problems sound like dirty contacts. First on the J-Wires of the keyboard, and second on the connectors going to and coming from the different boards, and third possibly on the legs of some chips that are on sockets. A good cleaning of all of those seems in order, IMHO.

Hi

Any idea how to clean?

Compressed air or some form of liquids?

But the questions remains, why does it starts to buzz after an hour or so...?

Any good sites for buying spare parts?