How do powersupplys work? (or help me fix 3 of them)

[office boy]

I'm talkin suppa duppa technical.
I have three that have failed, and I need top get one or two of them going. One just wore out and the 12V leg is gone. Some weird fanbus like thing my brother made zapped the other two. Those are almost new (but no warranty (don't ask))
I figure I should be able to figure what?s wrong and cannibalize from one to get another working, or go the "the shack" and get the parts I need to fix all of them.

So the question is, who can tell me really technical like how a power supply works, or does anyone know of a site that breaks it down nice?
Any help would be great

 

[office boy]

Come on anyone?
I know we have some electrical engineers here, now your chance to show your stuff.

 

[office boy]

^

 

[RossGr]

Ok here is what you need:
complete schematics for all of the Power supplies
soldering iron
Digital Voltmeter
oscilloscope

at least 2yrs of tech training on how to use the above.

Have at it.

 

[Windogg]

Also get a dry chemical fire extinguisher because if you're asking how to fix it because a "fanbus" type project went wrong then it's a sign to trash them while you're ahead.

Windogg

 

[beer]

Or for a more helpful answer, see Target PC :: Switching Power Supplies. Gives a fairly good explanation of it.

IMO, if you asked how to repair them, you are not qualified. Switching power supplies are incredibly complicated devices and for their retail cost, just buy new, reliable ones. May I suggest the Enermax EG351P-VE (FC) ATX power supply. The enermax is arguably the BEST power supply out there; this is a $57, dual fan, RPM-monitoring 330w/350w peak power supply from a reputable seller with 1 yr warranty.

 

[beer]

LOL I shorted out an AT power supply on my first fanbus project Windogg! LOL what a coincidence. All smokey and stuff...I just blew out the flames though...dad never found out theehehe

 

[office boy]

OK, the fan bus thing was my bro, not me. (And nothing blew up or smoked, it's just clicked off, and then wouldn't start. There is -12V and -5V but no positive power {except the green switch lead})
I have built and repaired many simple electronic things before, so I think I can (maybe) hack through this. The only thing is I don't know what to expect (what the circuit layout should be, or the working principals behind the functioning of power supplies)
And thanks for the link Elemental007 it gives me a start.
Any others? (A build your own would be dope)

 

[nasty]

btw, have you checked the fuse?

 

[office boy]

yep fuses are all ok. (I wish it was that easy )

 

[office boy]

Bump for the early AM crowd.

 

[MasterMind]

Probly a burnt cap. Check the PCB for burnt spots or the caps (little green things) for gooey stuff leaking out. If you find a bad one then desolder and replace it. If it's anything else it'd be eaiser + cheaper to replace the PSU.

 

[Gothmoth]

i think only experts should work on a powersupply so i dont give you an advice!!!

if you dont know what you are doing, you can make a DEADLY mistake.

its not that harmless as overclocking or replace a videocard,
you should KNOW what you are doing!

 

[Dulanic]

The main thing is to look for a burnt component or a cap where on the top it looks like it bubbled up or broke usually with some liquid coming out the top. If nothing burnt or there is no bad cap its time to pull out the multimeter and oscilliscope