sundance-communications.com/forum Forums TDM Business Telephone Systems Comdial Telephones & Systems DSU Dead -- Almost

Hi,

I have a G0408 installed in my house and I'm having some problems.

I think that the power supply section of the board is going, but I'm not enough of an electronics guru to nail it down.

Known:
Line voltage, good -- clean power
Unit powers up, the system status light comes on, blinks once, then winks, and then is on VERY faintly
After being plugged in for a minute, it starts to smell HOT.
Exhibits this behavior with or without the station wiring and line wiring conncted.
When connected, the stations display "communication error"
The transformer is providing output of 30VAC on the orange leg and 15VAC on the purple leg.
The big white squarish resistor(?) just past the power connections to the board gets wicked hot.

I've cleaned all the contacts, checked for shorts, looked for arcing, etc. I can't see anything and I suspect some component failure.

Can anyone help me to troubleshoot further?

It was working fine for months before it started to do this monday night. No storms, etc.

Thanks ,

That squarish resistor most likely is a fullwave bridge rectifier. (4 diodes) They do run warm to the touch. Unless your extremely into electronics, I suggest you replace your cabinet. There are several outfits that repair Comdial DSU's however, American Phone once owned by Comdial now by King Technologies still does the best repair. Of course that's just my opinion.

Jwooten,

Thanks for the reply, I appreciate your opinion. If it was you in this predicament, would you "replace" the cabinet, or send it out for repair and refurbish?

I'm contacting American Phone to get some more info now.

Thanks again,

That's a tough call. The supply houses have DSU-II's w/4phones for under six hundred. That's half price. You can,t buy the phones for that. I would expect your repair is going to be in the 2-3 hundred price range and Sundance may have some used ones around. It all depends on your budget!

https://www.telbroker.com/product_details.asp?product_id=67
They have on listed for $495 if you need to replace it. Give them a call. They always seem to help me out when needed.