Sir Kepo . . . . .
All of the clues are there . . . .
FR varnished board circa . . . a . .la . . . . .1976-1977
It is being a Motorola brand and they
OWN that very specific casing profile
MJE802 . . . . . NPN Motorola darlington
Fill us in on what the numbers are on the two small signal plastic transistors.
The wire bundling is covering up the marked PINK part . . .suspecting it to be another 1N400X family power diode or a low value resistor..
If so, confirm silver polarity bands position.
To start on analysis feed us the 12 DC voltages being read on the C,B and E's of the 4 transistors.
The BLACK wire and the outermost encircling foil path is your ground referencing.
Also take a reading ACROSS the WHITE marked diode that is probably being your ZENER reference diode for the regulator proper.
I could not see the metal thermal side of the bottom 802, but expect the left terminal to be the Emitter and the far right being its Base . . .with the central C being a given.
BOARD LAYOUT . . . .
73's de Edd