Strong electrical humming from unit

[BillP]

Hi!

I have a Back-UPS RS 1500 which started to give a strong electrical humming about two weeks ago. I have checked with the fan, but it is not the source of the noise after testing the power unit on and off, the fan starts but just change the pitch of the noise and then turns off and the humming resumes. I tried with a complete cool down of the power unit shutting it down for the weekend and powered it up again. The noise was fairly low on cold start and only increase with time to a strong electrical humming noise (over a 24 hours period). The power unit is not warmer than usual from touch (compared to another of the same model working near it). I only have a single tower computer plugged in and it barely draws a third (259 Watts) of the maximum power . I checked with the software and there seems to be no problem noted by it nor does it seems to affect the computer plugged on it. The power unit was fairly silent over the years (had a change of batteries last year) and as I was away for a couple of weeks I cannot say what could have caused the power unit to start humming that loudly... any help to get it less noisy would be appreciated.

model: Back-UPS RS 1500

Serial number: 8B0730R17199

Firmware revision: 8.g9a.D

Software version: PowerChute Personal Edition 3.0.2

Manuel self-test: 2016-09-03

Result of self-test: passed

[BillP]

Hello Francine,

I am sorry to hear that you are having trouble with this Back-UPS and the humming noise that it is emitting. At this point there is not much that we can tell about what is causing this humming, it is not a common issue that we have seen with these units. 

Have you at any point removed the batteries and unplugged the unit? We call this a "braindead" and it essentially reboots the internal processor. I would recommend you do one, and from there, we would have you start the unit on battery, and see if the humming is there, and then plugging the unit in to run online. I know that it gets louder as time goes on, but this is one thing that you can do. 

I put the serial number into our database and it told me that the UPS is from 2007, almost 10 years old. These type of UPSs typically have a life cycle of 5-7 years. The humming could very well be electrical components that are starting to fail. I would recommend replacing this unit. Our UPSs have come a long way since these units and we have a Trade-UPs program where you can get a discount on a new unit and we dispose of the old unit at no cost to you. You can call our sales at (800) 800-4272 if you would like to find more information. 

Thanks, 

Shanon

[Anonymous user]

Hi..i am a new user here. As per my knowledge this is a "braindead" and it essentially reboots the internal processor. I would recommend you do one, and from there, we would have you start the unit on battery, and see if the humming is there, and then plugging the unit in to run online. I know that it gets louder as time goes on, but this is one thing that you can do. These type of UPSs typically have a life cycle of 5-7 years. The humming could very well be electrical components that are starting to fail. I think you should replace this unit.

lead free assembly

[BillP · Accepted solution]

Thank you all for your tips, I have tried to restart the unit from battery only but it just changed the type of noise to one that sounds like a runaway clicking, but as soon as I replug the unit and that the battery turns off the humming restart again. I am going to change that unit using the offer from Shanon. I think it has outlasted its useful life, after all 10 years of constant usage is not bad at all! 😉