David, clarification understood, thanks. I sometimes have problems with a desktop; I reboot (because of memory leaks) and have to shutdown because the mobo refuses to restart (seemingly because of temp) but a couple minutes cooldown does the trick. Peter
On Nov 26, 2007 12:58 PM, David Mathog <[EMAIL PROTECTED]> wrote: > "Peter St. John" <[EMAIL PROTECTED]> wrote > > > I understood that sometimes the voltage from a fatigued (?), > > overheated (?) PS may fail the mobo's bootup requirements (which can > > be stricter re: voltage variations than running requirements) so > > sometimes a PS has to cool down before the PC will reboot. So > > particularly, sometimes a PC failing to reboot promptly is a symptom > > of the PS not max healthy. > > Subtle difference between "ignoring reset switch" and "failing to > reboot". I guess the symptoms might appear the same if the reset is > actually applied but the motherboard never gets far enough into the > startup sequence to generate beep codes or put any of the BIOS info up > on the video card. Even so, I still don't think what we were > observing was power supply related. For one thing these motherboards > could get into that state (unstartable until unplugged) even on a normal > shutdown followed by a lengthy off period allowing everything to cool > down substantially. And one or two boards would enter this state more > or less at random on any full cluster shutdown. (So no indication of a > particular bad node.) The 10-20 second "unplugged reset" time is fast > enough to drain charge from an electronic part, but probably not long > enough to lower the temperature much on an overheated part, especially > one within the power supply if the fans are not running. > > When I've seen iffy power supply problems the symptom has usually been > "random crash for no good reason", not "won't start". A totally blown > supply won't start, of course, but it's easy enough to confirm that > diagnosis with a power supply tester. > > > Regards, > > David Mathog > [EMAIL PROTECTED] > Manager, Sequence Analysis Facility, Biology Division, Caltech > _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
