Help... micromoog scaling issue

The Moog Forum Moog Music General Topics Forum
1

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

2

Check if the keyboard scaling is off.

3

“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))