Question How can you test to see if a PSU has definitively gone bad?

[80251]

I have a 13 year old Rosewill Capstone 750 Watt 80 Plus Gold that turned out to be the whole reason I had unstable overclocks w/my 9700k (@ 5.2Ghz.). The thing is, according to HWiNFO64 and my DMM, all voltages are always within the 5% margins specified by the latest ATX standard and usually higher than the referent voltage. On swapping PSUs though all the problems w/my present overclock disappeared. I'm guessing the ripple voltage must have been really bad under load, but I guess there's no way to test for this without an oscilloscope.

 

[steveb1976]

there are devices out to test "psu, and its cables" check amazon and ebay... they are cheap to buy and hand to have.

 

[Syntaximus]

There's always the paperclip method, but using a multi-meter is better.
Lots of guides out there (all similar for the basics), here is one is from Microcenter.

 

[steveb1976]

https://www.passmark.com/products/i...supply voltages are,and current for each rail.

 

[80251]

https://www.passmark.com/products/inline-psu-tester/index.php#:~:text=Download-,Inline PSU Tester,your desktop PC power supply.&text=Check power supply voltages are,and current for each rail.

For $434, that certainly isn't a cheap piece of equipment but it sounds like what I was looking for. Thanks.

 

[steveb1976]

i was showing you the device as an example of what to look for... you can get them in the U.S.A and U.K for a fraction of that price.

 

[geofelt]

The only way I know of is to replace with a quality replacement of sufficient power.
psu operations are complex and simple voltages do not tell the whole story.

 

[Grobe]

There's always the paperclip method, but using a multi-meter is better.

The paperclip method is only useful to test if the PSU is completely dead.

However, a common failure of many CPU's is that they tend to degrade over time in such a way that they cut power at much less wattage than rated for.

Another common issue about paperclip + multimeter method is that when no load, even a bad PSU may seemingly be healthy - because you may read a steady +12V voltage.

 

[Eximo]

PSU load testers are quite specific. The PSU testers on the market that are affordable check the voltages, hold up times, and ripple for the most part They still can't tell you if the PSU can handle a load.

13 years is well beyond the service life of the main capacitors. It should be replaced as a precaution regardless.

 

[80251]

@Eximo
I did check the caps on removing the PSU, the electrolytics all looked good (no leakage or bulging).

On further testing it seems like the old Rosewill Capstone 750Watt might not have been the issue w/my CPU core overclocks, but it had other weird issues. Occasionally anything connected to the SATA power connectors would disappear (HDDs, ODDs) and I'd have to power down the system and plug/unplug the SATA power connectors to get them working again.

 

[Grobe]

PSU load testers are quite specific.

Yes totally agree, but I assume most users asking about bad PSU doesn't have quick and easy access to such a tester - if not specifically telling so in the first post.

 

[geofelt]

The ONLY way to determine if a PSU is bad is to replace it with a new or known good PSU.
If such is not available on loan, buy are placement from a shop with a good return policy.
Expect to pay a 15% restocking charge if you need to return it.

As an anecdote, the cpu on a pc failed. I replaced with a new cpu.
The old CPU was still under warranty and I returned it to Intel where it was confirmed defective and was issuesd a refund.
The new CPU worked fine but I got occasional blue screens that I could not figure out.
Bios updated, driver updates, new windows, all failed after a few hours or days of use.
Tested on a new identical motherboard.
No indicators of a faulty psu.
Drove me crazy.
I replaced with a back up psu and all was well.
In retrospect, the bad psu may have caused the original processor to fail.

Bottom line, if you suspect a psu problem, replace it with a good one regardless.
A psu with a 7 to 10 year warranty is likely to be of good quality.