9V to +5V
The 9V from the monitor is regulated down to two rails of 5V.
This is done on a long PCB located on the black heatsink. The rails are named +5A and +5 B. During debugging it should be possible to connect a +5 V lab psu with current limiter on each rail of the PCB have be unconnected. In that way a more gentle startup can be made to avoid smoke during first startups
+/- 17V to +/- 12V
The +/- 17V power comes from the monitor and regulated to 12 V levels.
The +/-12V supply lines are only used for RS232 levels and on the ABC Bus connector. So for starting up the ABC 80 it is not important during debugging.