Have a site that a new SV9100 was installed to replace a Norstar MICS on March 12th and on April 9th it crashed. Pulled all the cards and tried starting with just the CPU but nothing. Tried doing a factory restore and a software upgrade but CPU wouldn't even see a USB drive, lights came on solid and didn't go beyond that. NEC shipped a new CPU and a new SD card, restored the database and away it went.

Customer called April 30th - system crashed again. Symptoms are exactly the same, won't boot up, won't read a USB, just dead. NEC is now shipping CPU, SD card and chassis in case it is a power supply or backplane issue.

System is plugged into a UPS, albeit a smaller one that has a network switch plugged in as well.

I have never had another site fail like this,, let alone twice in three weeks. Not sure what else to check or what might be causing it banghead ideas?

Thinking of a separate, larger UPS and possibly grounding the chassis, but admittedly, that would be a first for any NEC system I've installed over the years.