I think I'd stick a a logic probe on the output of each section of that
339 in turn and see if you get any activity when you unplug or stall a
fan. Of coruse we dont yet know that he genuine shutdowns are caused by a
fan problem. But I guess you could also montiro the outpus fo the 339
when a real shut-down occurs.
It's a surface mount chip with tiny pins and it's buried under a bunch of
wires going to the power supply. I think I'll try to explore other avenues
first.
likely temperature sensor.
The manual mentions a couple of jumpers which it says can be set to generate
a machine check rather than shutting off the power when there is a fan fault
or temperature fault. This looks worth a try now that I know the fan monitoring
I wonder what these jumpers are actually connected to...
I tried changing over the two jumpers. It's been running now for several hours
without either shutting down or writing anything interesting to the error log.
Unfortunately I forgot to bypass the interlock so that I could take the cover off
and unplug a fan to see what happens without having to switch off the machine
and start again.
Why do I wish there were scheamtics of this darn
thing available...
That would be nice.
Regards,
Peter Coghlan.