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Model D Minimoog Tuning Issue
Posted: Thu Dec 20, 2012 11:52 pm
by jcoplin
I just did a major overhaul on my Mini and now I have a weird problem. Everything works perfectly except I cannot tune the Mini to A440 correctly. I cannot get it to play A440 on the 16' setting, I have to go up to 8' to get a440. Basically, it is an octave too low and no combination of the trim pots will allow me to bring it up to tune. I have checked the supply voltages and everything there checks. I also checked the supply voltages at the oscillator card and they also all check out. This affects all three oscillators equally so I assume it would have to be something "global" to the tuning. Any ideas?
James R. Coplin
Re: Model D Minimoog Tuning Issue
Posted: Fri Dec 21, 2012 8:05 pm
by MC
pitch wheel? master tune pot?
Re: Model D Minimoog Tuning Issue
Posted: Fri Dec 21, 2012 9:50 pm
by MC
rear panel PITCH CV input jack?
Re: Model D Minimoog Tuning Issue
Posted: Sun Dec 23, 2012 8:04 am
by Electrong
jcoplin wrote:I just did a major overhaul on my Mini and now I have a weird problem. Everything works perfectly except I cannot tune the Mini to A440 correctly. I cannot get it to play A440 on the 16' setting, I have to go up to 8' to get a440. Basically, it is an octave too low and no combination of the trim pots will allow me to bring it up to tune. I have checked the supply voltages and everything there checks. I also checked the supply voltages at the oscillator card and they also all check out. This affects all three oscillators equally so I assume it would have to be something "global" to the tuning. Any ideas?
James R. Coplin
My mini plays A440 (utilizing only osc 1 on a square wave with filter open and no resonance) on the 8' setting at the A key just above "middle" C. Is that what your mini is doing? If that's what's happening your mini is functioning normally.
Re: Model D Minimoog Tuning Issue
Posted: Sun Dec 23, 2012 8:07 am
by Electrong
Also, who performed the "major overhaul?" yourself? A qualified tech?
Secondly obviously a note at the 8' setting should give you the same tone at the 16' setting only played one octave higher (on the 16') setting. Nothing sounds out of ordinary though.
Re: Model D Minimoog Tuning Issue
Posted: Sun Dec 23, 2012 8:41 am
by Kevin Lightner
My guess is the pitch wheel is in the wrong position in reference to its shaft.
If you performed a zero-detent mod on the pitch wheel, this could happen, especially if the wrong resistor was used internally or was never installed.
What exactly was done on the work performed?