On Fri, Jul 18, 2014 at 4:33 PM, King Beowulf <[email protected]> wrote: > On 07/18/2014 03:59 PM, Denis Heidtmann wrote: >> On Fri, Jul 18, 2014 at 2:32 PM, King Beowulf <[email protected]> wrote: >>> On 07/18/2014 12:37 PM, Denis Heidtmann wrote: >>>> Narrowed down to a problem with the standby 5V. The MB has an LED >>>> which indicates that the standby 5 volt supply is on. This LED >>>> flashes when the problem occurs, indicating overcurrent, shutdown, >>>> repeat. The two times this has occurred it went away spontaneously >>>> (Nothing I was doing can be said to be the cause for the problem going >>>> away.) I watched the LED while unplugging back cables (keyboard, >>>> mouse, USB, etc) one at a time. Nothing changed the status. Then >>>> while doing nothing it suddenly changed--the LED became steady on. >>>> Then the thing started fine. >>>> >>>> The computer is often completely powered off--no AC to the power cord. >>>> Other times it is off with AC on. On the 2nd occurrence it was in the >>>> latter state when I attempted to start it. >>>> >>>> The PS is a 380 watt Antec. >>>> >>>> I am open to suggestions on how to diagnose this problem. My first >>>> though is to measure the standby 5V to see if it is marginal. I have >>>> to see where is the safest place to put a probe. >>>> >>>> -Denis >>> >>> What's the history of that Power Supply (PS)? Age? Stuck straight into >>> the wall? UL 1449 surge power strip? UPS? Any good Lightning Storms or >>> power failures over the years? >> >> These questions point to the possibility that the issue is with the >> PS. Agreed that it could be the problem. How to diagnose in the >> absence of a spare PS is one of my questions. >> >>> >>> How many doodads are plugged into your system that uses 5V? All USB >>> devices do. CPU fan is 12V but some case fans run on 5V. DVD/CD/hard >>> drives use both 5V and 12V. PS wattage is not as important as the >>> current (in amps) the 5V and 12V rails can support. The biggest current >>> draw is when you are firing it all up. Perhaps the PS just can't push >>> rated current anymore. You can monitor the voltage off of an unused PS >>> connector when you power up and run. >> ... >>> Ed >> >> >> The problem does not occur with the machine running. It is the >> Standby 5V that I need to check. It is not at the unused 4-pin >> connectors. The USB appears to have 5 V on it when the machine is >> off. I will check that the next time this issue arises. >> >> What I gleaned from my web searches is there are basically two >> possibilities: The PS is flakey in that it produces insufficient >> current to meet the standby needs, or some component demands more than >> it should. What things use standby 5V? I have a mouse, a keyboard, >> an external serial hard drive with a separate power source and powered >> off, an internal serial hard drive, an internal dvd, and a (gasp!) >> floppy, on-board sound, and a flat-panel monitor. My guess is that >> the keyboard, the monitor, and possibly the mouse at least sense the >> standby 5V. All of these external things got unplugged during my >> test. I suppose a broken front panel switch could be the problem, or >> a scraped wire thereto. >> >> -Denis > > Doesn't lok like a lot of current draw anywhere (not like my spaceheater > of a system...) > > You can also check your BIOS to see if any built in doodads support wake > up/power modes. Many network chips support 'wake on LAN' (WOL) for > example. If its an integrated NIC, you can turn that off to see if it > helps. > > It could be, as you say, as simple as a bum wire or switch: IIRC, the > only reason, separate from WOL, to use standby 5V is if your power > switch hits a TTL relay to turn your system on (ugh!). ...
-Ed I do not know if it is TTL, but it certainly uses a soft power switch. (I expect that is universal.) Progress on this will have to wait until it fails again. Could be later today; could be next week or next month. -Denis _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
