Moog Polymoog -1975


User Manual: Analog Hell or Manual Manor
Reset Proceedures: N/A
Operating System code: N/A
MIDI or other control protocol: N/A
Software related Links: N/A
Patches or knob settings:
Circuit Overview: below
Scematics/Service Manual: fdiskc archive or Analog Hell or Christian's site or Manual Manor
Common Service Issues/Tips: below
Parts Sources: Keys knobs semiconductors misc
Uncommon chips/modules used: MK50240 TOS, MM5823 6 stage divider, uA726 transistor pair, DM8670 'polycom', CA3080E
Modifications:
General Info Links: Vintage Synth Explorer





Circuit Overview:
     Two 'ranks', a square and saw, are generated from uA726 based oscillator circuits. The two divide down networks with MK50240 TOS's are waveshaped on the saw side. An individual 'keyer' card for each key contains a vca/vcf chip. There is a toggle for using those filters or the moog filter which turns the machine into a paraphonic synth instead of full poly. (ie. one envelope for all the notes rather than the individual ones on keyer cards which are only accessible as 'presets'.) The presets are programmed by resistor packs on the front panel boards.

Service Tips:
     The machines are notorious for interconnect problems and bad wire connections onto them. The dividers and TOS chips fail sometimes to create 'interesting' variations. Solder job is massive on these and sometimes marginal. Be forewarned. I sent 20 hours reconditioning mine and I need to give it another look at. I still haven't found an actual ALLIGNMENT PROCEEDURE! Anyone? The service manual is a must on this one anyway. A lot of modulations going on and all discrete circuitry. Full width mother board on the bottom witht he 71 key cards standing up, then three boards over the top of all that with the oscillators and control i/f on the left, the 'mode' cards in the middle (which are voicing cards for each preset), and the moog filter and other stuff on the right. THe divider network and power supply are on the back of the unit and a board runs all the way across the front with the digital control stuff and the programming resistor packs. MASS circuitry. And lots of potential problems. Several op amps were bad on mine also. It was a basket case but at 140 bucks...what do ya expect! :) The bright side of polymoog is that they are a great experimentor's machine. Good ones people ask a high dollar for but a basket case one like mine you can often get pretty cheap. And there are tons of fun mods to be done if a person wants to experiment.

Parts:
I have many parts but got my NEW manual and dividers from Mike at Modusonics. It's a nice notebook manual if you want to go all the way.
Contact Sound Doctorin' Also DB Electronics had the polycom chips as well as some other parts like transformers.