It's working, but unfortunately it has one dead IG00155 VCF (on lower LPF card) This caused voice #3 on lower keyboard to be silent. It turned out, that not the whole chip is fried - it's first op-amp works, so it passes the signal unchanged to its HP output. So I swapped it with chip from HPF board, and now the voice ~works - although of course it sounds different than the rest as it doesn't have HPF. Looks like I need to get IG00155 - but they're so expensive
I'm going to do several mods to this keyboard:
- extending LFO speed control range (easy - just desolder one resistor)
- adding separate LFO speed control for lower manual
- adding couplers (as in E-70, circuitry is same, they just removed switches)
- adding "attack pitch-bend" (as above)
- adding flute envelope control - attack time and curve (there is already control for release time).
- adding missing Wave ROMs on VMS board and rewiring the whole thing to obtain dual-oscillator synth sounds (the boards are same as in E-70, they're just not fully populated / connected different way using jumper wires)
- making external programmer (like in GX-1) connected in place of one of the presets to edit synth sounds (filters, envelope and waveform settings)
And here's E-50 sitting in my living room.