I have a Power/Mate BPA-10E with issues. It is adjustable from
~2.5VDC to ~13VDC (The panel meter is 0-10VDC, so I assume that that's
what it should be adjustable throughout). I'm checking the output
with a calibrated Fluke 87, so it's not just that the meter needle is
offset or something of that nature. I'm trying to figure out what's
going on in the unit. Does anyone happen to have any schematic or
service manual for this unit? The unit regulates properly on both
current limiting and voltage regulation, but it seems to be offset by
~2.5V. It's possible someone modded the supply to run at 12 or 13V so
they could run car equipment or something like that, I don't know the
history of the supply, I just don't want to be using it if something's
wrong. I suspect that a voltage reference in the regulator circuit
has gone high, all I've found are three zeners, two 13V's and one
6.3V, I haven't gotten them off the board to test them yet, and I'm no
good at reverse engineering from board to schematic and these zeners
might not even be the original parts. Any thoughts on this subject.

(note, how do the "pros" test zeners? I want to see if I test them
the same as you guys)

Same song, second verse. This unit has five output transistors (one
drive and four outputs, from what I can tell). Their labelling is

QP0010
274
date code

Any idea what these original transistors are? Via diode test they are
NPN devices. This supply is 10V 10A, linear, so assuming they
dissipate maximum voltage of 10V, maximum current of 2.5A each, they
are 25W or so (I know, very brutal calculations, please don't tear me
apart for it). Should common new transistors such as 2n3055's or
something along that line work? Any idea what the originals are, what
their ratings are?

I know the info is vague, but any help is appreciated.

Thanks,
Steve