Error LED showing on E250

I've got an old E250 server where a front error LED is showing. I've read through the Sun docs (Sun Enterprise 250 Server Owner's Guide - Sun Microsystems) but it's only the 'General fault' LED (About the Status and Control Panel (Sun Enterprise 250 Server Owner's Guide) - Sun Microsystems) showing - not one of the specific LEDs.

prtdiag and /var/adm/messages don't show any errors and I can't track down what's causing it.

Anyone have any ideas?

are you able to get onto the RSC for this host?

You should be able to probe deeper via the rsc for further hardware/environment information.

Are you able to do a cold boot for the server? Prior to that ensure that the PSUs are ok.
If cold boot still does not work, you may need to check into the console message or boot the system in diag mode to go deeper. alternatively, perform a obdiag or POST test.