BK650EI high frequency noise

[Anonymous user]

I have bought a BK650EI UPS a few days ago and as soon as I plugged it to the wall socket I noticed a high frequency noise coming from the UPS, the type of noise made by a bad or faulty switchmode power supply. According the the warranty state check on the website, the UPS was manufatured in July 14, 2012.

The noise is quite distracting and irritating, I have noticed that when the battery is being recharged after a discharge the UPS is completely silent, which is what I expected this UPS would be (except when working on battery). My experience with a BK650MI which I own, and a Back-UPS RS 1500 LCD is that the units are completely silent when they are on standby and have their batteries fully charged.

I have recorded the noise and from the spectral analysis it seems to be a mix of frequencies above 10kHz with a pronounced peak around 12kHz so this is clearly not a hum related to the mains frequency.

I was wondering if this is a known problem with this model or series or if the unit should be replaced or repaired.

[BillP · Accepted solution]

I have no heard of this issue however I haven't personally dealt with any models other than US versions. Regardless, I would suggest you contact your local tech support for an RMA. If anyone else does have any experience with this frequency issue, please let us know.