smx1500 high pitch whistle

[BillP]

Hello,

I've just installed a new SMX1500RMI2UNC (APC Smart-UPS X 1500 Rack/Tower LCD - UPS - 1200 Watt - 1500 VA). It replaces one of the old SU1400INET models. It's configured as a tower unit in my office at home.

There's a really irritating constant high-pitch whistle from it. The culprit appears to be the main circuit board below the LCD panel. There's no fan noise, except when on battery or self-test.

Is this normal behaviour?

Colin.

[BillP]

There should be no whistling. I have an SMX1000 on my desk and I cannot even hear it running.

[BillP]

Although I can't call it a whistle, my SMX1500RM2U has a high-pitched buzzing that can be heard from 10 feet away in a quiet environment.  It seems to be very directional in nature (cock my head differently and the buzzing is mitigated) and I've learned to live with it for the time being.  Sounds like maybe a switching power supply or the LCD display multiplexer.

[BillP]

Thanks for the information. It's in an otherwise quiet office. The noise seems to come from the front part of the main board just above the battery. I'll talk to the APC support people about it.

Cheers, Colin.

[BillP · Accepted solution]

The unit was swapped for a replacement, which did not have the high pitched noise.