Datamath TI-2500 v2 schematics

[Marcovecchio]

I'm trying to repair a Datamath TI-2500 v2, but I can't find schematics anywhere on the web. The main problem is the circuitry on pcb's lower half, composed of discrete components. I'm guessing it's a power supply/regulator circuitry, and perhaps an inverter also, to supply negative voltages to the main IC.

All I have found so far are some high resolution pictures of the PCB (which helped somewhat) but it's not enough.

Any help is greatly appreciated, thanks!

Eduardo