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Weired scale problem

Posted: Thu Apr 03, 2025 10:01 am
by Salomonander
Hey guys,
I have a minimoog that has the following problem:

Oscillator 1 does not follow the keyboard. Meaning that if i play a scale, there is a point where the notes actually go down instead of up. The middle B is still good, but the following C is actually a Bb and so the D key is C so to say….
When switching octave, the problem still persists at the given position.
The other oscillators do not have this issue.

Where would i start the search? I did install new resistors on the right hand side of the oscillator board. Could i have messed up a value?

Thanks!

Re: Weired scale problem

Posted: Fri Apr 04, 2025 5:17 am
by Salomonander
Actually, it jumps back to an A not Bb. Any tips on where to start my search are very welcome. Im not a synth expert, so i dont really know where to start looking…

Im also wondering if it is possible to extract the flag poles of the duo tyne card edge connectors without the specialized tool. I have some really bad looking contacts and deoxid cant even get them shiny. The dedicated extraction tool is still available but it costs a fortune,

Re: Weired scale problem

Posted: Thu Apr 10, 2025 5:14 pm
by Salomonander
It turned out to be a bad solder joint at the summing 741 ic of oscillator 2. Somehow this messed up the tuning of oscillator 1. Its all good now.