Hi, I have Ultra 10 which used to work fine, but then started refusing 
   to boot. I thought it was due to dead battery in nvram module, which is 
   common for machines this old. I bought a new nvram module, set it to the 
   previous host id, etc. I managed to boot the machine today a few times 
   and then I started having the same problems. I doesn't boot, when I turn 
   the power on and off repeatedly, sometimes it starts booting, but then I 
   get the following on serial console before open boot diagnostic tests 
   get a chance to complete:
   
   Watchdog Reset
   
   scrolling across the screen, and then if I turn power off and on, it 
   doesn't even get that far, it just sits there.
   
   Any idea what's going on here?
   

sounds like the hardware has died :-(

i had a u10 in use the last ~2 years that died about a month ago.
i came home after a weekend away to a console full of SIR resets
and other badness and a fan running as fast as it could.  power
cycling gave a machine that after 2 times wouldn't even turn on.



.mrg.