Loud buzzing problem with Back-ups ES550VA

[BillP]

I have this ups one year now without any problem. Suddenly the ups began to make a loud buzzing noise especially when it working with the battery. The strange thing is that this noise passes and to the psu of television and i heard it and from there. The TV is a plasma samsung 6500.
I tried to unplug the battery but the ups still buzzing.
In my house i have and another back-ups the 700 without any buzzing problem.
Do i have to return ups to service or what else you suggest i do?
Thank you for any support

[BillP]

how do you get the buzzing to stop? removing the battery AND removing it from AC power?

with this type of unit, i am not sure there is much you can do. i'd just make sure it is not a piece of attached equipment causing it so if it was me, i'd disconnect every piece of equipment and turn the UPS on and see if you still get buzzing. if you do, then most likely it is the UPS. i'd pursue getting a warranty replacement if its under warranty or contacting support to see your options if you narrow it down to the UPS. you also could run it on battery and disconnect it from the AC power to rule out something like a ground loop (making sure all of your equipment is still unplugged).

[BillP · Accepted solution]

there is no way to stop the buzzing.The bussing is more louder when i unplug the ups and it works with the battery. I think i will go for replacement. Thank you for your answer.