High-pitched squeal (“coil whine”) from APC Back-UPS Pro Gaming every few minutes - how to eliminate?

[Rollinart]

Hello!

I recently (2-3 month ago) purchased an APC Back-UPS Pro Gaming (BGM-series) and have noticed a very high-pitched squealing or buzzing sound coming from inside the unit every few minutes. It’s not the normal beeps or alerts - it sounds like coil whine (vibration from inductors or capacitors), lasting several seconds each time and then stopping.

Details:
- Model: APC Back-UPS Pro Gaming BGM-2200B
- Firmware/Software: Latest PowerChute, UPS firmware up to date
- Load: ~200 W (desktop PC + monitor), constant
- Mains Voltage: Stable, within 230 V ± 5 %
- Battery Status: 100 % charged
- Input Sensitivity: Set to Low via PowerChute
- Self-Tests: Disabled periodic self-tests in software

Despite these measures, the squeal returns every 1-2 minutes. It does not coincide with on-battery transfer or error beeps; it’s purely a mechanical/electrical noise inside the UPS.

I have a video with this sound.
When running on battery power only, the noise stops. As soon as I connect it to the mains, the noise starts again.

Does anyone know how to fix it?

Thanks for any help!

[Teken]

Does the noise remain if you remove the connected loads while the system is on AC Mains?!? 

Validate by performing the following basic tests. Remove existing loads one at a time and observe the results if the sound goes away you found the culprit.

If the sound remains with no loads connected contact APC Technical Support to process an RMA.

If the sound goes away with no loads attached. Connect anything such as an incandescent light, resistive heater, hair dryer.

Report back what you observe and hear when these resistive loads are connected. If you have another computer system connect it without the monitor and report back the results.

If no noise is present connect the monitor and see if the noise appears or remains silent.

Questions Ask . . . 👍

[Teken]

Well?!?