Apc BE750 BB making a loud buzzing noise

[BillP]

Hi
My BE 750BB is making a loud buzzing noise when it is both plugged in and unplugged. There is no warning lights or anything. The unit is about 6 years old. If the battery is gone then I'll get a new battery, but I don't want to do this if the unit is faulty and waste my money.

Is there any way of telling what the problem is?

Thanks,

Steve

[BillP]

Hi Steve,

If a battery is bad on this unit it should emit a constant tone along with an alternating green and red LED. It is most likely that the buzz comes from an internal component of the UPS, it could be the buzzer or the inverter. Replacing the battery of the unit might not help fix the buzzing tone.

[BillP]

Thanks,

I was rather suspecting that a dead battery would give me some sort of an intuitive indication.. this does sound something like a bad inverter. It sounds very 'un-healthy' It scared us at first!.. wondered what the noise was as the UPS is buried at the back of the equipment!

It looks like I maybe in the market for a new UPS.

Any suggestions? I would like to backup my 27" imac along with its Pegasus R4 RAID Plus two WD 2TB external backup disks. I would set it to shutdown at the earliest.. just want enough juice to do it gracefully.

I think that the 750 that I currently have is a bit of an over kill!.. what do you think?

I did have one issue with the 750 and that is that it used to keep the computer awake. Despite my best efforts I never could get the computer to go to sleep when the USB was connected to the UPS. I hope that they have resolved this in newer models.

Thanks for the help,

Steve

[BillP]

I was just looking at the smart UPS's.. such as APC SMT750 Smart-UPS 750VA LCD 120V at Amazon [http://www.amazon.com/APC-SMT750-Smart-UPS-750VA-120V/dp/B002MZW5KE/ref=cm_cr_pr_pb_t?ie=UTF8&coliid...]

I was reading reviews etc and it seems the my new imac i7 may need a better sine wave output than my old G5 Power Mac.

We also have a standby generator so we need something that will accept a crummy sine wave input during a power outage

I looked at my imac's spec and it looks like it is around 480Watts plus of course the RAID and the backup disks. I was thinking that 750 watts would be OK???

[BillP]

Do you have the exact model number of your new iMac as well as the other equipment that you will be plugging on the UPS? If you also have their wattage and VA rating that would be helpful.

[Anonymous user · Accepted solution]

@smcrea - That model of UPS unit had a "recall" or some sort of technical notice several years ago; APC replaced all the ones I'd bought for my friend's restaurant rather quickly.