Strange PSU problem, it works, sort of, but...

sinip

Distinguished
May 24, 2012
7
0
18,510
Hello, my first post and hopefully someone will help me out. First of all to point out that I do have a lot of experience with repairing PSUs but this one had me for now.
So it is quite good looking and rated at 500W (though I doubt it can supply over 350) PSU made around Weltrend's WT7514L chip which works ok when jumpstarted with the wire outside of computer and all voltages measure good. I've also replaced all caps on secondary side on 3.3, 5 and 12V outputs. BUT... When I plug it to the computer and press power button, it will just start and then shut down after two seconds or less. "Power good" signal goes from 0.33V to 5.1V when jumpstarted so that should be good. But it refuses to work inside PC, which BTW works nice with another PSU.
So my question is, what I am missing here?
 

sinip

Distinguished
May 24, 2012
7
0
18,510
Well, thank you for advice but I'd prefer to have this one sorted out and learn something new in the process.