Question How can I protect my PC?

[Alowin]

So a few days ago there was a power outage in my area. I shutdown my PC which is connected to my UPS (https://www.cyberpower.com/in/en/product/sku/bu1000e). I left room and when I came back like half an hour later there was white smoke coming out of the back of my PC and it was "on" (the RGB was on). I left to get a fire extinguisher but by the time I came back the smoke had stopped but the burnt smell was there. I switched off my UPS and disconnected the PC. Now whenever I turn on the PC it would result in an MCB trip. So I opened it up and as far as I can tell there's definitely a burning smell coming out of my PSU but everything else seems fine as in nothing looks different (this was confirmed by a desktop repair shop person near me as well).
Now my question is how did my PC turn on? My guess is a power surge. The UPS is fine. My ultimate question is what can I do to protect my PC from further such events? Also PSU recommendations are welcome. I have a 450 W max draw setup and used a 550 W 80+ Bronze PSU.

 

[Ralston18]

Full system hardware specs and OS information?

Make and model PSU?

How old? History of heavy use for gaming, video editing, or even bit-mining?

 

[hedwar2011]

1) Is your PC setup to turn back on in the event of a power failure? (This is usually in the BIOS settings under power management) If so, disable it.
2) Are you certain you shut it completely down and didn't just put it to sleep? That could possibly explain why it was in the state that it was when you returned. If ever in doubt and something like that happens again, turn both PC AND the UPS off completely after you have saved everything you need.

 

[Alowin]

Full system hardware specs and OS information?

Make and model PSU?

How old? History of heavy use for gaming, video editing, or even bit-mining?

i5 12400F
RTX 3060 12GB
1TB NVMe M.2 SSD
PSU:GIGABYTE GP-P550B 80 Plus Bronze
Dual Booted with Windows and Manjaro Linux
Just over a year old and used for gaming(once every few days for a couple of hours), youtube watching, programming and nothing else.

 

[Alowin]

1) Is your PC setup to turn back on in the event of a power failure? (This is usually in the BIOS settings under power management) If so, disable it.
2) Are you certain you shut it completely down and didn't just put it to sleep? That could possibly explain why it was in the state that it was when you returned. If ever in doubt and something like that happens again, turn both PC AND the UPS off completely after you have saved everything you need.

Well to check the first I'll have to get a new PSU first, I think this one is still in Warranty so maybe I'd get one from them. Will let you know when the PC turns on.

I'm confident I shut it down, I was also having thoughts at that time that maybe I should turn the UPS off as well(idk why).

 

[bill001g]

So you were running on the batteries on the UPS for some period of time ?

Although not real likely the UPS you have is not actually designed to run modern equipment. You see this more on a generator but it is the same issue on UPS.

Modern power supplies because they are so efficient require very clean power and in particular want a clean sine wave signal. Many UPS like yours are simulated sine wave.

Some power supplies tolerate this more than others. You will see reports of power supplies turning off as soon as the UPS goes to battery. You will also find information that non sine wave power can damage a power supply. How valid this is I feel is somewhat suspect since it mostly comes from UPS manufactures trying to sell you a more expensive UPS.

Could have also just been your power supply was older and running on the poor power from the UPS killed it.

If you are lucky you will just have to replace the power supply. You have to be rather careful about lower end power supplies. It is hard to get a quality 550watt power supply there are massive amounts of crap ones sold because of the price. I suspect that is also why there is such a jump in the price between a 550 and a 750.

 

[Alowin]

I mean since the power was out the UPS was on battery yes but still the PC was shutdown(not OFF since I didn't flick the switch at the back OFF). I hope it was just a PSU defect and a new PSU wouldn't have same issue and I'll be more careful and flick the Switch OFF when not in use that way I think there can't be any damage.

 

[bill001g]

If the pc was shutdown already when the UPS went to battery mode it is very strange it would cause any issue. There is almost no power usage.

You pc always pulls some tiny amount of power unless you turn off the switch on the power supply. So during that time it technically was running on the UPS but the power draw was so small it wouldn't matter about the quality of the power.

In addition unless you buy a very expensive UPS there is always a tiny outage that the power supply will see when it switches between the city power and the battery inside the UPS. The capacitors in the power supply normally hide this. This though should not damage the power supply it is designed to run that way for people that do not have UPS.

Could just have been the power supply was defective and the next time you unplugged it was going to fail anyway.

You now have to hope the power supply did not damage anything else in your machines. Since it was already shutdown your chances are better.

In the end they always say you should unplug your machines when you are not using them so thing like power surges and lightning to not damage them but nobody does that and it is rare you see a issue like yours.

 

[Alowin]

If the pc was shutdown already when the UPS went to battery mode it is very strange it would cause any issue. There is almost no power usage.

You pc always pulls some tiny amount of power unless you turn off the switch on the power supply. So during that time it technically was running on the UPS but the power draw was so small it wouldn't matter about the quality of the power.

In addition unless you buy a very expensive UPS there is always a tiny outage that the power supply will see when it switches between the city power and the battery inside the UPS. The capacitors in the power supply normally hide this. This though should not damage the power supply it is designed to run that way for people that do not have UPS.

Could just have been the power supply was defective and the next time you unplugged it was going to fail anyway.

You now have to hope the power supply did not damage anything else in your machines. Since it was already shutdown your chances are better.

In the end they always say you should unplug your machines when you are not using them so thing like power surges and lightning to not damage them but nobody does that and it is rare you see a issue like yours.

Thanks everyone for the responses I'll post here further once I get a new PSU. Also anyone has any PSU recommendations for my setup that wouldn't start burning (XD) feel free to comment.

 

[bill001g]

You might want to start a new thread and ask for recommendations. You will likely gets lots of opinions. Power supplies are one of the hardest things to determine quality on since even very large name manufactures make garbage lines of power supplies. Pretty much though the really cheap stuff is junk.