View Single Post
Old 07-29-2012, 01:52 PM   #11
Join Date: Jul 2006
City & State: southern california
Posts: 28
Default Re: Need tips in fixing APC 1500VA UPS having buzzing noise

Originally Posted by Toasty View Post
Correct. Surge protectors on INPUT to UPS, not on output.

Having them on output side can also present a load/short to the UPS which it tries to compensate for by boosting output. A vicious circle.
Things like this make me say "ignorance is a bliss". All the while I had been buying surge protectors and I have only one power tap I got at Walmart. Now I either need to remove the protection PCBs from the strips I have or buy new taps

Originally Posted by Toasty View Post
I think the unit is fine and just gone a little noisy. You could replace them and the problem will remain. Because the noise is load variable, I would be scoping the output for spikes or looking further back in the circuit.
I was afraid something like this might be up, but read on (I don't want to put in $50 in parts + a weekend of my time behind a lost cause)

Originally Posted by Toasty View Post
Try a paper towel roll as a "stethoscope" to pinpoint the noise. Try moving components with a wood or plastic tool to see if they're just resonating from the switching circuit. It's why PSUs have that glue/caulk around coils and caps.

They make noise when making power. Nature of the beast.
I gave it a closer look today - the EPCOS is surely making th noise - I touched it with a plastic rod and I could feel it vibrating. I touched the other components around the region with it and could feel nothing.

Surely this confirms the source of the noise once for all?

Originally Posted by Toasty View Post
PS: I'm now seasick from watching that video....

Some folks have -NO- camera skills...
Actually I PM'ed the guy for his feedback, so we should see him on this thread
vsmGuy is offline   Reply With Quote