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My 10 months old PC ran into a problem some days before. My system specs are as follows:
- Intel Core i7-8700 Processor
- MSI Z370-A PRO Motherboard
- 8GB RAM
Here are the details about the issue.
Most of the times, the system restarted instead of shutting down while there was no power from the mains. In other words, while the UPS (Numeric Digital 600EX-V) was on battery.
Sometimes it was unable to turn the system while in the same situation as the above point.
I was able to turn the system on if the second situation didn't occur or if I connect the power cable directly to the source without using the UPS. In that situation, the system randomly restarted while using. This was quite rare and hard to reproduce.
Note: It is not a software issue. I checked it in multiple OSs.
Because the 3rd situation happened regardless of whether it was connected to the UPS or not, I just concluded that either a part other than the UPS or both the part and the UPS is causing the problem.
I wasn't wrong. After a lot of trouble, I could find out that the PSU (Cooler Master MWE 450) was faulty. After replacing it, all three issues are gone.
But I am still confused about one thing: Because 1st and 2nd situations happened, It is clear that the UPS output is different while in normal and backup mode. Is it normal? If not, isn't the UPS faulty too and is it the one which damaged the PSU?
When you use the phrase, "Backup mode", you are talking about a situation where you are powering the devices while on battery (i.e. you have lost main power). – Ramhound – 2018-12-06T19:15:22.427
1Yes, you are right. – Bertram Gilfoyle – 2018-12-06T19:24:04.027
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That's a 600VA UPS. What does your system draw? It could easily be more. Note that I don't mean "what's its power supply rated to?" but really what does it use in practice, counting all devices attached to the UPS (presuambly monitors, but hopefully no laser printers!). You can guesstimate using this tool if you can't measure it.
– Chris H – 2018-12-07T10:42:39.047It's quite plausible that the UPS can deliver more current from mains than it can when supplying from battery. If you exceed the current that the UPS can supply the voltage will drop one way or another. (Ideally the voltage drops straight to zero in such a case.) – kasperd – 2018-12-07T16:25:10.600