Moog Prodigy Issue

i love my moog prodigy but there is one problem with it… the modulation wheel does not function. i’ve taken it apart but i’m not sure if it needs replacing or what. the wheel turns but nothing happens.

does the modulation wheel do the same thing as the modulation knob?
if not - where can i find parts for a moog prodigy?

make sure the OSCILLATOR MOD and/or FILTER MOD switches are on…they need to be on for the mod wheel to have any effect. and turn the MOD RATE control up halfway or so, too.

hum… both are on but it still doesn’t seem to work… does the mod wheel do the same thing as the mod rate knob?

no…the mod rate knobs adjusts the speed of the LFO from slow to fast. the mod wheel lets you dial in the amount of LFO modulation…

i hear modulation when i flip the modulation switch - the modulation wheel must be set at some volume, maybe the middle… is there a default volume if the mod wheel doesn’t function? I am afraid of loosing the flat head screw on the knob - it seems like it is on the very tight - i don’t know if that would do any good. any suggestions?

i would leave the wheel alone…check the pot, making sure there are 3 wires coming from it, and that the plug those wires connect to is securely connected to the main PCB. if you have a meter, check the pot (10k) to make sure it’s still working…

http://www.hylander.com/images/schematics/moog/MoogProdigyServiceManual.pdf

the schematic is on the last page…mod wheel at the bottom, around the middle (l-r)

i’ll have to check that - do you think if i can still hear modulation when i flip the switch that the pot works and it may be a connection issue? or can the pot not work and you can still hear modulation?

a pot is a variable resistor…the mechanism which causes the variation may be broken, leaving the pot functioning more like a fixed-value resistor. if this were the sutuation, the modulation circuit would function, but you’d lose the ability to alter the amount of modulation

well - i fixed the issue today. after checking all the connections - i went back to the screw - which was cross threaded. basically, the wheel was moving but the resistor was not… by adjusting the screw, for some reason it gave it resistance and started to work! maybe stuck over time… i bought this prodigy with a broken knob and the mod wheel not working - now both are FIXED - how’s that for added value! Thanks for time…

sweet…added value is always a good thing :smiley: