[sdiy] The Aelita 321 synth.

[John Henson]

Hi All,
Most if not all of the issues with this Aelita were with the Digital 
Oscillator board which sits on the floor of the case next to the crazy 
power supply. The front panel controls for Octave and waveform select 
send Digital signals to this card and most of these signals were 
intermittent, the oft quoted interconnects were totally shot, and 
hardwiring the wires to the board improved the working of the synth a 
lot, I got most of the synth working except for the bottom 16 keys of 
the keyboard. The contacts were good, connectivity to the Oscillator 
board seems good, but no signals derive from this part of the keyboard.
There is a connector marked X9 near this section which has nothing 
plugged in and the pins on it don't do much, the schematics from 
ruskeys.net show pictures of pcb's that just don't exist in this synth, 
and the schematics themselves are unintelligible, and the keyboard 
scanning system uses more than 200 diodes in two grids on the back of 
the keys and on the Oscillator board, I have checked all the diodes and 
I don't think this is it. My frustrated and remaining question is, was 
there a Daughter board plugged into X9 which I am missing?

Regards to all,
John.