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Memorymoog modulation OSC offset

Posted: Wed Oct 26, 2016 7:10 pm
by rjd2
Hi folks, I'm wondering if anyone has any ideas on an issue I have.

Working on a non-plus MM. The problem: activating the "osc _ freq" button in the modulation section creates a pitch offset on the respective VCO. so, for example, if the machine is tuned to exactly zero, and all the VCO's are tuning up perfectly, pushing the "osc 1 freq" button in the modulation section pushes the pitch up of osc 1 by about 40 cents. it does this with each osc, respectively, so "osc 2 freq" button pushes the pitch of osc 2 up by about the same amount. same w/ osc 3. so there is obviously an offset that needs calibrated, somehow.

i've followed the factory calibration procedure from psu thru the vco's. the modulation section calibration mentions nothing about a modulation offset. i'm kinda stumped. any ideas? thanks, rj

Re: Memorymoog modulation OSC offset

Posted: Thu Oct 27, 2016 4:10 pm
by rjd2
scratch that-mods, you can delete. swapping U12 on the common analog board for a new 741 solved the issue.