Moog Prodigy: Pitch and Mod Wheels strange ranges

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GregoryK
Posts: 12
Joined: Tue Jul 26, 2016 12:33 pm

Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by GregoryK » Tue Jul 26, 2016 12:36 pm

Dear forum members,

I have a late Moog Prodigy, model 336A.

Currently, the Pitch Wheel transposes 9 semitones up (C4 - A4) and 11 semitones down (C4 - C#3). According to the manual, the Pitch Wheel range should be “Greater than ± perfect fifth”.

Also, the Modulation Wheel (in it’s maximum position), while in Oscillator Modulation, transposes 17 semitones up (C4 - F5). According to the manual, it should transpose up to 12 semitones only. (And if I remember correctly, the Mod Wheel used to work correctly before)

As far as I can see from the part numbers, printed on the installed pots, they are original Moog parts: 10K Linear pot for the Pitch Wheel and 10K Special Taper for the Modulation Wheel.

I'm not sure if these types of pots are right for the Prodigy: I have the Prodigy parts list in PDF, but there's no information about the types of pots for the wheels. The schematics only says "10K pot". And Syntaur.com sells the same part for both Wheels for the Moog Prodigy.

I would greatly appreciate any information or hint. I'm trying to figure out if the problem is in the pots or the source of the problem is somewhere else.

Thank you!

Stevie Ray
Posts: 254
Joined: Sun Apr 17, 2016 2:25 pm

Re: Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by Stevie Ray » Tue Jul 26, 2016 7:56 pm

Sounds about normal for a Prodigy to me. These are not precision instruments. If you don't like the pitch bend or mod range you could wire in some 10K trim pots in series (above and below) and set the range according to your tastes.

GregoryK
Posts: 12
Joined: Tue Jul 26, 2016 12:33 pm

Re: Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by GregoryK » Fri Jul 29, 2016 1:33 pm

Thank you very much for your input, Stevie!

The thing is the ranges of both wheels have been changed during the last couple of months, so I'm thinking it might be an indicator of some problem inside the synth. I think I should start with checking the voltages, since the wheels are connected to both +12V and -12V.

GregoryK
Posts: 12
Joined: Tue Jul 26, 2016 12:33 pm

Re: Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by GregoryK » Sat Jul 30, 2016 7:38 pm

I checked the outputs of voltage regulators 78M12C and 79M12C, and the voltages are +12.13 V / -12.12 V, which seem to be normal. Probably I should do a calibration procedure and see what happens then.

djzaga
Posts: 1
Joined: Wed Jan 08, 2014 11:50 pm

Re: Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by djzaga » Wed Jul 11, 2018 5:54 pm

Whel I have a problem with unstable pitch wheel so a friend tested the pot and told me to replace it, I order from syntaur and the pot arrived the only issue is that the shaft is slimmer so the wheel it completely loose.
I pust some tape in the shaf and force the way in for the wheel but I think thats not the solution the shaft shoulf fit correctly. beware of that if you buy the pot from sinter

atkbg
Posts: 62
Joined: Fri Dec 03, 2004 2:10 pm

Re: Moog Prodigy: Pitch and Mod Wheels strange ranges

Post by atkbg » Fri Jul 13, 2018 1:48 pm

djzaga wrote: the shaft is slimmer so the wheel it completely loose.
Hopefully you saved your original pot. disassemble it and the new pot. Put the resistor element from the new pot into the old on. Close it up and you're good to go!

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