Circuit Overview:
These machines are a 3 oscillator divide down synth of extraordinary interest. They cloned the moog filter design and there is an envelope (Attack (ataka!), Decay/Release, Sustain) for both amplitude on the left by keys with master volume, and on the right by the filter cutoff, resonance and amount. The lfo controls are on the bottom of the fold down face for speed, vibrato and VCF mod amounts. Each oscillator may be selected for vibrato. And mix (a little overkill given that there are also volume sliders for each but oh well. These soviets were control freaks! :-) ) The span of tuning on each oscillator is disappointing and I'd love to figure a mod someday to expand it just a bit. Wont' quite catch a fifth! Master tune on left. Then tunes, footages (one at a time) and waveforms (""). Below tuning sliders are buttons for legato, unison (giving overbearingly insanely thick sounds that makes us think 'cold war' all over again) and a string bbd effect. The digital stuff and power supply are below and analog stuff in back on the fold down panel.
Troubleshooting tips:
The power supply filters weren't too hot. Failed in both I worked on. Some connections/bad solder were also common. Latest...keys started dropping out on the low end. At first I would wack on them for a while and the notes would come back..for a while.
Parts:
Some of the parts cross I believe and if you can get a cross reference always feel free to ask or check my Parts
Contact Sound Doctorin'