Hi Gil,
Probably there is a variation in the cv voltage
that controls the oscillators.
I experienced similar issues on the osc 1 of a
RA Moog model (the first earlier version) and the only thing that solved the
problem was replacing the 2n4058 transistors.
Please, provide more info such like serial number
and if your oscillator board has only transistors or 2 ICS SG3821 or
CA/LM3046 or 3 UA726 ICs.
Regards,
Paulo Palmieri
----- Original Message -----From: GilSent: Thursday, June 28, 2012 9:55 AMSubject: [vintagesynthrepair] Minimoog D pitch driftingI'm handling a friend's mini, which acts strangely. The overall pitch (of the entire machine) will change suddenly, up and down, not to far from the correct pitch but a few semitones... It affects all oscillators at the same time. Is this a known issue in old minimoogs? I would usually suspect either power supply main voltage instability, bad caps or transistors, but being it affecting all 3 oscillators, I tend to think it is not oscillator circuit related ? :/ I'm new to minimoogs so any help would be appreciated... Thanks !