NEC NEAX2400 RGU Alarm Issue 1

[TechPlus Communications]

New to the forum. I want to preface this post by saying that I don't work that much with NEC, I work primarily on Mitel products and I inherited a client that has three NEAX 2400s (the rest of their systems are Mitel). For the past 4 1/2 years, I've been able to muddle my way through fixing the mounting and inevitable issues that have arisen with the 2400.

I now have an issue that I haven't been able to resolve.

The RGU Alarm LED was lit on the SPA-55-UA card and as far as I could tell from the several random extensions I tested, none of the extensions (analog) on that top shelf were generating a ring tone (I tested with my butt set directly to the 66 block).

I have quite a few power circuit cards for the 2400 that appear to have the same specifications, but, I don't have one with the exact SPA-55-UA model number, so, I replaced it with a new PA-PW54-A card and... no change.

There are 704 analog extensions and none of the other power circuit cards are having this issue,

I would really appreciate some guidance here from the NEC pros in this community.

Thanks in advance.

 

[belevedere]

The PW-55 is the primary PSU. The PW-54 is the redundant/backup PSW. If you have both in the same PIM, then shut off the PW-55. The PW-54 should take over without any interruption in service. Most likely a fuse on the card, however they do have a microcomputer chip on board to provide intelligence to the CPU's. There is a reset button on the card. Pressing that should reset the chip. If you have full power redundancy (2 power cards per PIM), then shut down a good working PW-55, let the PW-54 take over in that PIM. Then swap it with the bad one. See if it comes on with the same error. In that case you may have a short in a cable run, or some device plugged in that is not a SLT device.

 

[TechPlus Communications]

I should clarify.

There are not two cards per PIM in this system. There's only one.

If you're telling me that the 54 is a backup, then I will replace it with a 55, but, first I'll frog the cards as you suggest.

I'll follow up.

Thanks for your help.

 

[TechPlus Communications]

I used one of the 55s I had and it fired right up.

It's been operating for two days without issue.

Thanks for your help.