What will a blown psu capacitor do?

[Carl Patrick]

Basically I plugged in my power supply and it made a pop with a park followed by some smoke and a burning smell and most people would say it's a blown capacitor and so if the capacitor had blow could that possibly fry the entire system?

 

[lakimens]

If it isn't fried already, I wouldn't try that PSU again. Just get a new one of higher quality.

 

[Eximo]

Depends on which capacitor, but you shouldn't use any electrical device that has thrown off sparks or smoke. Buy a new power supply.

 

[BFG-9000]

I had this happen, and the system actually fired up and ran fine, although the next day when the capacitor finally dried out it could no longer start. I replaced just that capacitor (it was on the 5v line) + the PSU has worked fine ever since and it's been 10 years!

It's nearly always a secondary capacitor that blows in a PSU and those are used to control ripple on the outputs. Without a working cap on one of the rails, the voltage on that one output would be extremely dirty and possibly even noisy enough to damage something, although usually if it's bad enough the PSU will shut itself down after a second as it will never get a power-good signal.

I actually prefer the bulging/exploding capacitors as then there is no question which one is bad. Many cap brands like OST simply dry up through their seals so the only reliable way to test those is to unsolder them all to test outside the circuit, which is clearly too labor-intensive to ever consider repairing.