No clue either...
To sum up:
- There is no problem on the 'computer' hardware parts as you are able to start the computer with an ATX PSU
- You are able to start the computer when the PDCB is connected to an external brick, so the PDCB is also fine
-> then the only remaining part that can be faulty is the PSU
But
- The PDCB output values when attached to the PSU give good results on the tester
-> so the PSU seems to be working as expected, at least when there is no power draw or very few
Don't you have another setup that requires less power to test your PSU with? Like a motherboard with an embedded CPU drawing 20W from the wall or something.
Or having the PSU to take care of the motherboard only, and the ATX PSU for the CPU?
If that's not risky for your hardware that is, just thinking aloud here...
Well maybe it's time to summon our 12V chief magician [USER=294]@Thehack[/USER] !
