Repairing power supply ?

[snowdog]

Hello,

Bought a 2nd hand Coolermaster PSU, a Coolermaster rs-430-pcap for some pocket cash.

This PSU worked fine before, I believe the seller, he looks like a reputable guy who sells a lot of stuff and he offered me to refund the money without having to give back the PSU. He says it's always worked fine in a pc, and been gathering dust for 2 months after removing it.

So, I plug it in, nothing, just 5VSB/indication led, but it won't turn on.

So follow up with the classic paperclip method ( short green wire with black wire, make sure to have some kind of load on the PSU though, so I had a dvd player and a 120mm fan hooked on it). It started.

Plug back in a Mobo > it fails to start with both the power button, and paperclip method. The moment I pull the 24 pin plug ( note that I already removed AC power), it starts up again (with residual power in caps, as paperclip is still in place connecting green and black).

What could this be, some kind of short protection ?
I checked over the caps in the PSU and can't see any abnormalities ( leaks or swells, etc...).

Any ideas what part could be the culprit ? Does anyone know of a good guide for fixing psu's/electrical components. Or does anyone see any abnormalities here:

 

[bledd]

Unless you know what you're doing, get a refund and don't fiddle.

 

[Monkeynut]

Some of those capacitors are clearly bulging at the vents at the top and need to be replaced. We'd need to know the series on the side.

 

[snowdog]

Unless you know what you're doing, get a refund and don't fiddle.

I already have a refund, that's beside the point, I still want to fix it/learn... I've replaced electircal parts before ( eg. replacing MOSFET in aircon/heat blower resistor in car or fixing audio amps or diodes on hdd's). Electrical parts are dead cheap from various sources and soldering/replacing components yourself saves you a lot of money.

Some of those capacitors are clearly bulging at the vents at the top and need to be replaced. We'd need to know the series on the side.

Which ones, perhaps the pictures show it wrong, but from what I can see none of them are bulging, they are perfectly flat on top. Unless I'm blind .

 

[Deleted member 651465]

Bear in mind the capacitors will hold charge for a while, so not advised that you go opening it up unless you know what you're doing.

 

[snowdog]

Bear in mind the capacitors will hold charge for a while, so not advised that you go opening it up unless you know what you're doing.

Yes, X capacitors might hold a dangerous charge, usually not an issue with power supplies except the cheapest nastiest Chinese ones, as any branded one will always have a bleed resistor.

Plus you can short them anyhow before working on em, there's no danger with working with a psu that has been unplugged for hours.

It's a bit hard to learn what you're doing if you can't practise, isn't it, have to start somewhere. What's with this huge stigma of working on electrical components ? It's a low power Pc PSU, not a Microwave or CRT tv.

EDIT: Now that I checked again I can see 1 or 2 caps that are indeed slightly bulged, can't see it properly, I'll remove the PCB from the case to see it better.

 

[tyler_jrb]

I'd agree. I took mine apart once. But having said that there was one american who took his PSU apart touched the wrong spots and was killed. Always best to discharge the caps and test to ensure they are safe. caps can hold charge for a long time without being discharged.