A customer has a Partner messaging module with a port expansion card in slot 5 of a 5 slot cabinet. The module has failed and been replaced 3 times over the last year. When the customer calls into the module (intercom 777), its just RNA. Resetting the system or reseating the module doesn't help. I replace it, it works for a few weeks/months then happens again. The processor module is R4, which works fine as well as the other modules in the cabinet. Any ideas as to what is causing this to repeat? I hate to throw money and parts at a problem at a 20 year old system, but the customer will not upgrade.

Have you tried replacing the 5 slot carrier? Maybe a ups for the power for it so it gets clean power.

I thought of that. It’s possible there’s a bad slot and the site does have power outage issues. I’m posting to see if anyone else had this problem also

Dirty power or quick power interruptions (off-on-off-on, flickering) will kill the power supplies in these systems. Give them a good UPS. I've been happy with Minuteman 1000VA.

Then I would change who you are getting your replacements from if they aren't giving you a 1 year warranty.

Forget about replacing the carrier. They can't cause that type of problem and I've never seen one go bad anyway.

-Hal

My distributor does give me 1 year and has been great replacing the unit and support. I'm with you Hal, I've never seem a cabinet go bad either. I'll quote them a UPS and cross my fingers that takes care of things