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UPS killed my PSU?



Hi dear community. Recently I’ve been experiencing issues with my PSU. When I go to turn on my PC it just clicks on and off 90% of the time. After it does that the PSU is “locked up” so I have to turn it off and back on to turn my PC on. This has also been happening trying to wake the machine from sleep. The machine has not been throwing any kind of error while on and it’s completly stable. I tested it without the GPU and with one stick at the time but it does always the same thing. I’ve immediatly took the machine off of the UPS but still no progress. With a different older PSU everything works flawlessly.

The PSU I’m sending back for RMA after 3 years is the CM V650S semi-modular gold rated. The UPS it was connected to is this. Do you guys think I did something wrong pairing those two or it’s just that the PSU gave up? Further specs of my machine are in my profile.


From what you’ve written here, I see no evidence the UPS is the culprit.


I’ve started wondering that’s what was the cause because I’ve never had a PSU getting so damaged on me before. Also during the most intesive tasks I’ve always been near the 50% mark on the PSU load so should’ve lasted me for a while. It wasn’t that dusty either since my case has a dust filter for the PSU that I regularly clean. Do you have any idea about what happened?


It broke.

It happens. If you don’t trust the brand id suggest going with another brand of PSU for the next one.


I won’t buy a new one, is still under warranty so I’m arranging the RMA with the seller. If the seller refuse to take it I’ll talk directly to CM.
Next time I’ll go for a Seasonic modular I think.


Run that UPS with the older PSU for a while. My gut feeling is that your PSU failed of its own accord but if it happens again you’ll know for sure something else is causing it. At least you got 3 years out of the new one. If the company that made it honours the RMA I’d say you should stick with them and buy a backup from them as well. Meh, that’s how I play anyway. Kingston honoured a HYPER X SSD with the warranty off by replacing it with a brand new SAVAGE so I bought 4 more from them. lol :smiley:


I could run the old one but the 12V is not stable (jumps frequently between 12V and 11.9V) and the 3.3V is 3.392V so I don’t trust it too much really…
If I had money to buy a new PSU I would’ve done that but I don’t. Also having multiple PSUs is a waste for me. I got unlucky so I’ll just wait patiently.


11.9V Is totally within ATX spec though for the 12V line.
same goes for the 3.3V line.

Supply (V) Tolerance Range, min. to max. (V) Ripple, p. to p., max. (mV)
+5 ±5% (±0.25 V) +4.75 V to +5.25 50
−5 ±10% (±0.50 V) −4.50 V to −5.50 50
+12 ±5% (±0.60 V) +11.40 V to +12.60 120
−12 ±10% (±1.20 V) −10.80 V to −13.20 120
+3.3 ±5% (±0.165 V) +3.135 V to +3.465 50
+5 standby ±5% (±0.25 V) +4.75 V to +5.25 50

That said Voltages are no good sure-fire indicator about PSU quality.



…or UPS quality. It says pure sine wave, but if the UPS is broken and it is letting out a bunch of ripples, it can be quite damaging to the power supply, the same way that a power supply can be damaging to components. The ripple is measured with an oscilloscope, one that can go to very high frequencies non-the-less, which can get quite expensive. Best bet is to find someone who already has one and knows how to operate it.

Still though, as Eden said, things break in strange ways and for different reasons. Component malfunction due to wear and tear is very plausible, even with brands who have decent components and QC.

I still think it’s the PSU breaking on its own. If there are multiple alternatives, it’s your best bet to trust the least complicated one to start out with.


It’s an Antec HCG620 bronze non modular PSU, it’s not a cheapo chinese grey PSU so I guess I could run with it in the mean time. Thanks for posting the rails specs, I really appreciate it.
The V650S was dead on with every voltage when looking at the BIOS screen.


Yeah, it could also be the UPS that damaged the PSU but I can’t really check it or be sure about it. Seems like it’s woking flawless really. I might try installing the software for it again to check on it.
The PSU issue is weird, it’s like trying to start a lawnmower pulling a cord. If you try at least two times it starts and I can’t see any other issue with it, the PC is 100% stable, I can game, stress it, the fan is still inaudible.

I linked the UPS I bought so maybe you can tell me if it looks decent. To my knowledge it’s a really good UPS that shouldn’t have any issues. Also I’ve always turned it off at night because of the bright LCD screen on it, so less wear I suppose.


The specs on the UPS looks alright, pure sine wave is always a treat and 700W should be more than enough with your usage. Mind you, I’m not in the loop with UPS atm, and don’t know the brand and such.

One thing I come to think of. In the 24 pin ATX plug, check that every wire is firmly, with no wiggle, attached to the little metal peg, especially the one called PS_ON (the green one, just search for atx 24 pinout). This may not be possible if it is sheathed, and you may void warranty by opening up the shroud.


I can check but it’s a casted plastic so my possibilities are limited. Also I don’t have the correct tool to take the pin out and put it back in. Also it’s under warranty soo I won’t poke at it too much. Thanks for all the help and suggestions, I really appreciate it!


Oh, don’t take it out, it’s not meant to be taken out. Just wiggle with the wire while looking in the hole where the peg is. Use a flashlight. If it moves significantly between the wire and the peg or you can see copper strings outside the peg, it could be the problem. The peg is loose in the casted plastic plug, and is supposed to, just fyi.

Anyway this is just a thought, and could be a false positive, even if it does look loose to the untrained eye.


I checked it and everything looks absolutely fine.
But my retailer will refund me 100% without sending the PSU back so I’ll buy a new one when I get the money. I’ll buy a Seasonic this time.