Moog Music Forum

I am restoring a micro. I've replaced most of the op-amps and transistor arrays. I checked all of the voltages on the power and main board and they are within specs shown on the schematic. The trimpots all checked out with a digital VOM. Every front panel control works to produce sound accordingly. I have metered every trace for opens and shorts to ground. I'm having this problem that xanthene had posted some time ago. ( I've been trying everything and I can't seem to be able to solve this OSC Scale / OSC HI problem. When I try to tune the Hi F, the OSC Scale trimpot is fully CCW and the Hi F is off by -20% of a perfect F. As for the OSC Hi, it is always fully CW and off by about 20%.)

Noted problems:
The voltage to the resistor string was 2.16 vdc not 2.58 vdc
The oscillator hi trimpot has no affect
The oscillator scale has a range of about 1 semitone

Anyone know ? or have an idea ? xanthene, did you ever get a response?
Thank you all for your help.

ms-5
sonic six
arp quadra
alpha juno 1
yamaha sy55
korg triton
Thanxs winbyte

Check if the keyboard scaling is off.

"The wheels on your car are missing. Have you considered looking to see if there are wheels on the car?"

Harumph!

Yeah, old thread. Well, I have a tremendous scaling issue on my micro. I think it's a heater issue. I'll ask somewhere else, since this seems to be a dead end.

((pokes the rotted-out pan of his Micromoog with a pointy stick despondantly))