Moog Music Forum

I might have found the correct circuit. It seems to also power some leds. I dont need that. But could i get away with the part of the circuit that i marked in green?

I think i have it working now. I was measuring with reference to ground… stupid me.
I now have both probes on the diodes, each on one side of the pack. Was able to trim to 0.00v with a 100k trimmer that i inserted like in the the attached ribbon mod and i now have a steady 0.05v on the input of the ...

Resurrection of a dinosaur.
But does anyone maybe have the schematics for the opamp version or one with the trim pot installed?
Also, when you talk about measuring 0v across the diodes, do you mean the junction towards the wiper, or the junction going to the 27k resistor and oscillator board ...

And one more issue :( When playing the highest register, only oscillator 3 is clean. Oscillator 1 and 2 (1 especially) have sone low frequency dirt. Sounds as if some real low notes get triggert. The low frequency dirt does change pitch with the keyboard. I dont know how to explain it better. I ...

I can barely get this thing tuned… i use a frequency counter and get the pitch very close. But i cannot adjust it perfectly due to the rough trimmers.
So im not capable of getting zero beat. Any adjustment is too much. Whenever i mix signals i get some phasing. Hmmmm…. Does it just never get perfect ...

Thanks MC,
yes, i was chasing a ghost. Guess thats what happens if a studio tech works on a synth :) i think all is well now. I do struggle a little with tuning on the range trim pots. They are super sensitive and its almost impossible to get the 3520hz… is this normal behavior? Just wondering as ...

Doing some more reading…. Looks like this is normal behavior? Only the reissue is capable of being set to last note priority?

So i thought i was done. All happy. Until i realized that there is another issue :( goddammit! I dont know if this has always been the case or if i messed something up, but my keyboard isnt working properly anymore.
When i hold a key and trigger another one, the new note only plays when its a lower ...

And in case anyone is interested, i was able to get the bleed down a lot by soldering all sense lines on the card edge connectors. These were crimped only and adding additional solder helped.

And another question: how do people in the eu wire up their power light?
Its 125v and obviously we are running 230v. On my unit there is a 2k resistor and another part that i can not even identify in series (can you?). Is this legit? Does not look like this was done at the factory and the hot lines ...

Thanks a lot MC! Highly appreciated

And maybe you could help me solve the last issue:
I do have some osci bleed, even with all mix switches turned off. I did the vca calibration, but i can still hear it.

In another post i found this:

“The VCA is opened and closed by the current sink Q18 (Minimoog service manual). If there is an ...

One more thing: on all pictures i could find, the tempco resistor’s legs are bent in a very specific way. See picture. I wonder if this actually serves a purpose? Do i need to bend them in a similar fashion?

Thanks a lot!
That was very informative. I will go for the 3w 3500ppm. I did read at some places now that the 1/6w might actually work… but its TCR has a tolerance of 5% while the 3w is 1%. I guess i will have a more uniform result across the three oscillators.

One last question regarding my minimoog restoration:
Some tech before me replaced the tempco resistors on the old oscillator board with regular resistors. I want to correct that. But they are hard to find.

I can get them at the original 3300ppm but with a power rating of only 1/6w - the service ...