sundance-communications.com/forum Forums TDM Business Telephone Systems Comdial Telephones & Systems DX120 cabinet power supply squeel

I took my spare DX120 cabinet off the shelf last week to upgrade to F19. I did a final test before putting it back up and the power supply squeeeled when I turned it on and the system never booted up.

Tried it a few more times and sometimes it keeps quit and boots normally, other times it squeels and won't boot.

When it does boot up, I found several dead digital ports on the mother broad now. Time for an RMA it looks like.

First question asked by Comdial, err...Vertical was, "Is it grounded?" Yeah, it was.

Anyone seen this before?

I've done 3 and haven't seen anything that resembles your experience. Keep us posted. and keep it "grounded"

I'm not a phone tech, but as an electronics tech I know what usually causes the squealing in "aged" electronics are usually transformers. The short version is that transformers are coils of wire wrapped around a plastic core (which is molded around a steel/iron loop). Over time the plastic expands and the coil of wire gets loose. The wires then tend to vibrate and cause the squeal you hear.

Usually not a problem unless the transformer shorts out due to the painted-on insulation failing on the wire. There could be other reasons for squealing (including bad ones like overstressed circuits) but usually in stuff that runs 24/7 thats usually the case.

I've worked with switching powers supplies enough to identify its coming from the windings and how aging can affect them. But this power supply has only two hours use on it and been stored on a shelf in the office.

Comdial said the diodes are known to blow, or in this case "get leaky" for lack of better term.

If you determine the PS to be bad PM me.
Mark

"leaky diodes" :rofl: Where do they get these people?

"Leaky diode" is a common term.