Jason R. and John, Was the roach running a particularly intensive design at the time around the failure? Just wondering why this part would be failing. Is the current limit somehow being exceeded? Thanks, Glenn
On Tue, Jun 19, 2012 at 9:52 AM, Jason Ray <[email protected]> wrote: > The first time I was troubleshooting this problem, I did see a fault on the > 1V supply with roach_monitor.py. I didn't check roach_monitor.py on the > second roach because the problem was so fresh in our mind we just jumped to > the finish line and checked the mosfet with a meter, then replaced it. > > For reference, the part in question is Q13 (FD6675BZ). > > Thanks, > Jason > > > > At 09:33 AM 6/19/2012, Jason Manley wrote: >> >> Good sleuthing! >> >> FWIW, roach_monitor.py is supposed to be able to pull the log out of the >> Actel Fusion, which should have logged a fault on the 1V rail before >> shutting-down the board. This should work independent of PPC or dmesg >> states. I'm afraid I have little faith in the Fusion/Xport combo to reliably >> catch these issues, but it has helped me a few times. >> >> If it works, it only retrieves the reason for the last shutdown, so you'll >> have to plug a laptop into the Xport to query it directly after it >> self-shutdown. >> >> Jason >> >> On 19 Jun 2012, at 15:23, John Ford wrote: >> >> > Hi all. We've had a couple of ROACH failures with identical causes. >> > Maybe some of you have seen this, but it's worth keeping in mind in case >> > you have a problem. >> > >> > The symptom is that the ROACH would sort of power on, but then turn off >> > spontaneously. On one, as soon as the bof was loaded the roach would >> > turn >> > off. The other one would come on for a brief few seconds and then turn >> > or, or it would cycle on and off. The monitor readout in dmesg gave >> > non-sense readings. >> > >> > In any event, the cause was traced to the +1 volt supply MOSFET switch. >> > Replacing that mosfet fixed both roaches. Kudos to Jason Ray for >> > finding >> > the problem originally. >> > >> > John >> > >> > >> > > > >
