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Vintage Synth Repair

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Roland MC-4 issues with CV Output

2013-07-06 by monads

Has anyone experienced issues with fluctuating voltage on the CV Outputs?  

It's the CPU board (confirmed by swapping/testing another board). It doesn't output consistent CV voltages on any of the channels (1-4). They fluctuate, and a quick test is tuning with the MC-4, holding SHIFT and pressing #9 (Tune) to tune a VCO to A 440 Hz. The Total Tune calibration pot doesn't help either, it should operate perfectly in the center position but does not. 

Any suggestions on what areas of the CPU board I should focus on?

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