Memorymoog oscillator not working? (PITCH HI)

[LaxSlash1993]

A couple of days ago, I tried auto tuning the MM+, and it said 5 tuned. I ran checks with C7, and found that one of the oscillators was "PITCH HI." Is the oscillator supposed to shut off when this happens? I enabled the out of tune oscillator, and turned off the others, and when I tried using the out of tune one, there was no sound. I'm going to calibrate the VCA's, and tune the VCO's (I have a service manual), but I just wanted to make sure that this is normal behavior when a VCO get's out of tune to a certain point.

[LaxSlash1993]

Bump. Also got some more questions.

I started to tune the thing. I got voices A and B tuned, but noticed a couple of things that I wanted to ask about. When I used the HEX values, one oscillator read 7F perfectly. And so did another. But, when I compared the two, using FREQ CENTER, I got a very bad beating sound. So, I tuned it by ear as per the service manual, and when there was no beating sound, the oscillator was reading at around 6C. Tried to bring it back up to 7F, but got the same issue. Should I just leave it at 6C?

I also want to calibrate the VCA's, because some of the volumes don't match up. How would I do this?

Thanks.

[LaxSlash1993]

Bump. I'd like to have the MM calibrated ASAP... please help. I fixed the issue with the beating sound. Still need to know about the PITCH HI issue, though.

[LaxSlash1993]

Anyone?

[MC]

The trimpots go bad as they age. Also they didn't tin the trimpot leads when they built the voicecards, so when they soldered them it was not a good connection. I found this out when I could pull the trimpots out of the board with ease!!!

Other potential problem is bad S&H circuit.

[LaxSlash1993]

Yeah, I noticed that too when I was tuning. I was worried I was going to knock the trimpot right off the card. lol

Looks like it's time for a trip for service. Thanks for the replies on both topics, MC.

[Kevin Lightner]

I don't think it's so much that the leads on the trimmers aren't tinned well, but rather that the voice boards are single-sided and have no plated thrus.
Instead of being soldered all the way through a board, they're only soldered to one surface: a trace on one side of the board.
This is also why the voice boards have all those wire jumpers.
This was likely a conscious decision on Moog's part to save money over more expensive two-sided boards.
Same thing they did when making Polycom boards for the Polymoog.
Moog did use higher quality two-sided boards for the MM's digital circuitry though.