Help with an ATX Power Supply Low 3.3v

[rikkitikkitavi]

Two things - computer psus are almost always overrated. and if it dies due to overheating it is also unsafe, due to failing protection against high temperature. Clogged fans or heatsinks can also casue overheating.
unsafe as in everything from losing the data.you are working with up to fire hazards.

second- one successful repair would not be reliable statistics to me. Not that I doubt your.skills, the opposite judging from your previous.posts. Things pop due.to a reason and unless it is found, who knows when the.magic smoke goes next time?
that said I agree it.is good learning and if you know what you are doing I think it is worth repairing for the experience as a lesson. I have myself replaced primary caps on a few items, but never bothered with comp supplies because I have not got a rig that sized motivating a expensive supply .

[MarianB]

I have practically completely dissasembled and put back together many ATX psu's and althoug they are cind of tuff to work with, if you know what you are doing then it becomes easy, you need to understand as best as you can the building blocks of it, how do each work, what does each do and you will be able to do almost anything you want with them.

As long as it's architecture is ok and the board it's self is still in a good condition then any fault can be troubleshooted, usually the power semiconductors fail and sometimes theyr respective network, both easy to fix, many times dryed out caps causes failing and when not sure of theyr quality just replace them, they are cheap enough, a few other issues causes failing but rarely. In this case this unit seams to me it had it's protection threshold too high that combined with small heatsinks the power devices overheated and failed, if no smoke came out of the unit then most likely only the power transistors failed, and maybe the schottky rectifier ( but i stress the "maybe" ). It is fairly easy to remove the power devices, check them out, check theyr network and after carefully verifiyng everything else, power the unit back again and see what happenes.

[rikkitikkitavi]

That figures
It is the maybe that I keep thinking of...

I am worried that the overvoltage protection does not shut down.
CPU and GPU have their own step down supplies, but there is a lot on the graphics card and the motherboard that would fry, and also harddrives etc.
So unless I have 100% certanity about the cause of death of the supply, of it goes.

As you said, once you get the hang of it they are often easy to replace, single sided board and everything. Need a good soldering iron though, sometimes the secondary rectifiers are soldered to a copper area the size of Greenland...

I

[MarianB]

Originally Posted by rikkitikkitavi

sometimes the secondary rectifiers are soldered to a copper area the size of Greenland...

Verry true