Moog Music Forum

No answer? I also have the same problem. If you have the solution, please share. thanks!
jigsaw puzzle

Some thoughts:

If I understand the circuit correctly, Q9 and Q11 just form a current source for the kbd resistor string. The result should be 8.33 mA. If I am right, you just have to ensure to provide 8.33 mA. This can be done by any current > 8.33 mA and an addtional trim. So I am not sure that matching is that necessary. I would just solder transistor sockets and try it out. And if Q11 is still alive, just replace Q9.

And even with a current <> 8.33 mA the Mini should work if you just adapt the oscillator scale.

Or am I missing something?

The simplest way of matching transistors is to use a fancy active current source to drive a stable current through the devices one at a time and to record the individual Vbe(voltage) values. Then matched devices are selected based on the recorded values.