atcomsystems.ca/forum Forums TDM Business Telephone Systems Comdial Telephones & Systems Comdial DX-120 major issues

Hello to everyone and hope everyone is having a better night then I am. I have a Comdial DX-120 KSU1 that seems to have died. The heartbeat LED is dead and the KSU has alot of relay chatter when I power up. Also when I power up the unit it beeps really fast eleven times and than pauses and beeps another three times. I checked all my voltages and none of them are within spec. My -12vdc is -8vdc, -5vdc fluctuates really bad, +12vdc is +9vdc, and my +5vdc is about +4vdc. It seems my KSU is toast. My software version on the KSU looks to be version f18. Can I purchase another KSU1 mainboard with different software version and hook it up and everything work fine as far as my voicemail and my other add on cards and if so where can I find a KSU1 board at. They seem to be hard to find. Does anyone know what might be wrong with the KSU1 mainboard. I have checked all the voltage regulators and they all check good. Thanks in advance for any suggestions and look forward to hearing from you all. Have a good weekend!!

kkell11400

To find a KSU, contact the sponsors of this board--click the "Equipment" link on the top of the page--or call 1-800-766-3425. You're right, they're hard to find sometimes. If they don't have one, maybe they can get one for you or point you in the right direction. They can help you out.

It sounds like a bad power supply. What makes you think the main board is bad?

Justin

I was thinking the same---but no one wants to sell just the power supply. If it's the P.S--it's probably the Zener Diode that needs to be replaced--but unless you're proficient at soldering and de-soldering, and have a bag of Zener Diodes--it's much easier to buy a KSU and just replace.
We've got power supplies, boards, and Zener Diodes---but I wouldn't sell them either. These things go out a lot. It's one of those things that---if you are maintaining quite a few 120s & 80s---then this is what you have to do. If you're just servicing one DX120---then just replace the KSU. JMHO

When you guys speak of the power supply being bad are you talking the main power supply that feeds 38vdc to the KSU1 board. I checked it and it was good. I know there is a power supply circuit on the KSU1 board, but without a schematic it would be alot of probing. The 10vdc Electrolytic capacitors on the board were not in good shape. The tops were buldged out and two out of three were leaking. The voltage regulators checked good as did the zener diodes. Getting alot of chatter on the relays on the right side of the board. I found a KSU1 board and hopefully will get it tomorrow. It is the same software version as the KSU1 board I have. Let me ask this. Should my voicemail card and all other cards plug up with no problem. I'm a little concerned about the voicemail card because they seem to be finicky at times.

All cards and voice mail fittings were the same across the life of the DX120 series. You should be fine there.

I believe the "beeping" comes from the voice mail upon power up.

Scotty, your right the beeping on boot up is from the voicemail. I'm sure the voicemail card is fine. It's just the KSU1 giving me a fit. Hopefully I will get this thing in the morning and get it installed and everything will work fine. I'm keeping my fingers crossed.

The 408 board(bottom board with co's and digital stations) is bad and needs repair. If you have 36 to 38 volts dc on the hv test spot to the metal ground point just below the voltage test points and your voltages are bad the 408 pcb is bad. It is the #1 failure in these units trust me I know.