[sdiy] Minimoog tuning woes, Op-amp swaps?

[Oakley Sound]

 > the tuning between high A and lowest A requires a different scaling 
than, say, the middle two C's.

OK, this is the first problem you need to solve before doing anything 
else. It could be a keyboard problem or that, somehow, all three of the 
VCO expo circuits have been affected by the new resistors. To find out 
which you need to check the keyboard voltage. Hook up a DVM to the keyCV 
signal that goes to the VCOs from the glide circuit. As already stated 
it's not going to be 1V/octave, but you should still get a linear change 
across the keyboard.

It's worth pulling off the keyboard connector and cleaning both the plug 
and socket with some De-Oxit D5 and then wash out with IPA.

If the keyboard is producing equal volt jumps for any octave played then 
you need to now look at the VCO board. Was it playing more or less in 
tune before you changed the resistors? If so, suspect that you have 
perhaps a poor connection on the gold contact strips on the VCO board. 
It's worth cleaning the board side contacts with IPA - or maybe a wipe 
down with a bit of D5 and then wash off with IPA.

Tony

www.oakleysound.com                  Oakley Sound Modular Synthesisers