At some point in it's life, the CA3080 op amp at U24 was faulty (I assume). It was replaced by an RCA 314, which I can't seem to find any reference to online.
I had a spare CA3080, and swapped it in.
It immediately fixed the osc2 volume problem. Now I can overdrive the filters again!
I'm not sure if this info is helping anyone, but what the heck, I like it when people post solutions.
Jim
At 10:00 AM 2/22/2013, you wrote:
While looking for my Source owner's manual the other day I came across a printout with the parameter list and values. I'll check it tonight but it seems unlikely that osc2 is supposed to be that much quieter.
PT
From: Jim Blair
To: vintagesynthrepair@yahoogroups.com
Sent: Friday, February 22, 2013 12:25 AM
Subject: [vintagesynthrepair] Still more Moog Source weirdness.
So pitch calibration went great. However.....
When setting the volume of osc2, the data wheel will increase the
volume until the numeric display reaches 58, then the volume starts
dropping again as the display approaches 99.
But even at it's volume peak of 58, osc 2 never reaches the volume
of osc1 at 99. So I'm assuming the the osc 2 volume is reaching
approximately half volume, then instead of continuing up to full at
99, it just decreases back down to a quieter volume again. (In other
words, 58 is not the equivalent of a normal full volume.)
Very odd.
Jim