[rescue] Challenge L -12V overvoltage?

[Francois Dion]

Alright, the Challenge was sleeping for the past few weeks, and now 
yesterday I powered it back on and I got a message on the integrated 
display:
-12V supply over voltage (or something like that)

I powered it back off, then powered it back on. The error didn't come 
back, but it wont go thru it's post. Just a message stating that there 
is an error in the log history. Any ideas how to bring it back up? No 
console output whatsoever either.

Francois