Hi Neil,

nesesu wrote:
Perhaps if you said what the problem turned out to be, we could judge
if there might be any 'easy' way to track such a problem current. For

Ah, but that's not fair! "Monday morning quarterback".
The point of my question is, knowing *exactly* what I
knew when I sat down with this problem, what's the *best*
way to proceed.

It's sort of like asking *how* to locate your (lost) car keys
and being asked "Where did you *find* them?" :

example, it would be almost impossible to locate excess leakage
current in the PS output filter cap since it is 'inboard' of any
circuits that might have voltage/resistance given such that proper
current could be calculated from. It would also be difficult to use
heating of the cap as an indicator unless the 'normal' temperature was
known since such a cap can heat from ripple current/ESR [I^2*R],
leakage dissipation or just high ESR. Where practical, I substitute a

That's true of all components! I.e., you can look at a
schematic and not (easily) determine what the current
flowing through a particular node will be (unless it is
a simple passive network). Or how warm a component would
be, etc.

bench power supply for the unit's built in supply so I can monitor the
current drawn, but where the unit being tested has a multi-output
supply such as you describe, that may not be feasable.