Implementing the deadband hack as per the moog service

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johnmacattitude
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Joined: Tue Jul 13, 2021 1:43 am

Implementing the deadband hack as per the moog service

Post by johnmacattitude » Tue Jul 13, 2021 1:57 am

I've finally gotten around to implementing the deadband hack as per the moog service bulletin/synthfool hand-drawn schematic on my late osc board Model D. The deadzone works after inserting everything (including the 619K resistor), however the synth is now around 4 semitones flat! I double-checked everything according to the factory bulletin, and everything appears to be in order, and the voltage across the diodes is within specification (0v +/- 0.1v). I tried to re-calibrate it, but the trim pot maxes out before it can achieve pitch, indicating that something is wrong! When I tune the pitchbend pot, the voltage across the diodes reads around 0.4 volts, and the deadzone disappears no longer functional. I was able to remove the mod and the synth now functions normally, however reinstalling it causes the same issues.... Any assistance would be greatly appreciated.

Thanks in advance

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