[kln_nurv]

My quad 1Ghz Tezro seems a bit sick and I'm wondering how much it would cost to fix. It last worked about 3 months ago and I suspect the power supply is getting weak, but I'm sure that's not all.

Symptoms:
When I first turned it on this week, it shut down after a few seconds complaining about a low voltage rail on one of the VRMs, but not a VRM failure. After that, it has been consistent. 
Fans spin slightly and the machine powers off pretty much instantly with the message "power up error" on the L1 display. The front red LED blinks once.
The internal LED on the backplane is yellow, then red, then stays yellow when AC power is connected. The LEDs on the node board connectors are both constantly amber.
Sometimes L1 says fan 8 is doing 0rpm, but I have confirmed that all fans do spin when trying to power up.
If this was a normal PC I'd be 99% sure there was a short somewhere.

I have swapped the power supply for a 1000W SuperFlower ATX power supply, with identical results. I have also removed all PCI boards, leaving only the IO9 board installed. Even removing the RAM makes no difference. I have never removed the node board, so damage to the connectors is extremely unlikely. I have tried to use the L1 port for diagnostics but it doesn't work via a Windows or Linux machine as far as I can tell, and I don't have another SGI machine to connect to right now.

Thanks in advance for any suggestions.