Original PCBs

The left is the power board, the right the main processor board.

CPU (Hitachi HD6301V1P)

EPROM - (HN482764 - 8k x 8)

ADC - (M58990P)

and a bunch of 74HC138s for scanning + a few latches.

 

The power board uses oddly enough B744A power transistors and JRC4558 / 2903 OPAMPs for regulation, and also houses the MIDI signal output buffer transistor, a C2785.

 

I think originally it used like 4 C or D batterys, however I've just been using a 9V regulated via a 7805 (easy breezy).

Done