APC Rackmount UPS 1400 loud hums

[Anonymous user]

Ok just started recently.. my rackmount unit produce this humming sound. I removed all system attached from the output and still the humming continue.

Did a test on battery it is ok.
All lights are green.
Even if I unplug battery or shut off the unit it still hums.

It will usually hums for a few minutes and then stop for few seconds before starting to hum again. The only way to keep it quiet is to unplug the whole unit and not to use it. What is wrong with this thing?

I have created a video. sorry for the low lighting, but you can clearly hear he humming sound.

Link: [http://www.youtube.com/watch?v=Tju-8yqUXO4]

Message was edited by: fuji_man

[BillP · Accepted solution]

We can't really be 100 % sure based on the sound but it's likely a flaky component rather than a failed component(since there is no faults/alarms). We don't troubleshoot at the component level here so we usually recommend Trading it in. If anyone else had any ideas short of replacing the UPS, please reply.