SUN Fire-240 system power cycles at regular intervals

Hi Gurus,

We have a SUN Fire-v240 system which power cycles every 14 days at around
the same time and it has happened so far 3 times.  The logs are not showing
anything. The consolehistory is lost when it power cycles. Right now I have
a laptop to capture the console logs when it happens next. There are other
systems on the same Power Distribution Unit and they are fine and all are
connected through UPS. Nobody has physical access to these servers other
than System Admins. This is system is very old and  has been running fine
for years with no changes. We updated the ALOM and firmware after the issue
started happening but it didn't help. Has anybody comes across this issue
with SUN Fire-v240.

Thanks,

SK