3 Oct
2016
3 Oct
'16
11:44 a.m.
weird that it has two AC inputs
I wonder if it's actually two supplies in a single package
Probably not applicable to this PSU, but I've worked on SMPUs
where there were separate AC Inputs for the power supply for
the internal control circuitry (often feeding a little linear PSU
in the unit) and for the main rectifier/smoothing caps/chopper.
It was done for ease of servicing (they actually cared about
such things back then) You could power up the control circuits
and check waveforms. etc without any risk to the choppers, then
power up the chopper circuit from a current-limited supply so that
if anything went wrong the damage would be minimised (no traces
blown off the PCB, etc).
HP certainly did this in the PSU for the HP2100A mini.
-tony