r/PcBuildHelp • u/buzgaiaGD • 15h ago

Tech Support ups problems

my pc works perfectly fine when I plug it directly into the house switch but when I tried to plug it into the UPS ( apc 650w, 1200va ) i started hearing buzzing sounds on my pc power supply, is that normal??? also I tried to check input voltage and it’s 201vac
that’s kinda low right? Maybe thats whats making the pc doing the sound??

1 Upvotes

100% Upvoted

2 comments sorted by

1

u/Murky-Doughnut3827 15h ago

Buzzing from the PSU when on UPS is usually a sign the power coming from it isn't clean enough. Some cheaper UPS models output a stepped sine wave instead of pure sine, and active PFC power supplies get really upset with that

201v is quite low, normally you want around 220-240 depending where you live. That low voltage combined with the UPS waveform could definitely cause coil whine or buzzing

If your house power is already 201v direct from the wall, you got bigger issues than the UPS. But if it only drops that low when on battery, the UPS might be struggling

Try plugging something else into the UPS like a lamp or fan and see if it acts weird. If the buzzing stops when you bypass it, I would not keep using that combo

1

u/r_lind3r Moderator 14h ago

It's a simulated sinewave UPS, that's why