Working on a power supply. Just can't toss it without completely destroying it first. This PSU has almost no use and is out of warranty of course, so my lessons continue.
Upon close-magnified scrutiny of the components nothing indicates failure, i.e. bulging caps, burned FETS, broken wires, fuse, etc.
Primary Symptom: When green wire is grounded at main terminal none of the computer peripherals receive 12V, 5V and/or 3.3V. However , I do receive 5v on the standby rail. So the 168vDC being supplied to the +5vstandby rail is going through this smaller transformer and providing the correct voltage. I guess I am getting something to the secondary side.
The 400V cap is only showing 168V(dc) (waiting on cap tester now). Thinking this cap should be somewhere around 350-375V. This is the first discrepancy I find in-circuit. My second concern is the main transformer is not getting any power at all (red rectangle on photo).
Question: If cap is good what in the circuit would prevent it from charging to an estimated 350-375V?
I have added a few pictures indicating general observations from probing.
Image Notes (below):
Yellow arrows show general flow from introduction of 120AC.
Red lines on photos showing the top is where the board splits and goes to the secondary side.
Purple marks on photo showing the bottom-side of the PSU also show flow of voltage from introduction of 120AC.
Would greatly appreciate any diagnostic suggestions.