ATX restart troubleshooting.

[JonathanAnon]

Hi guys,

Have a couple of PCs at the moment that are rebooting on site. So we have the usual situation where you dont know if it is the PSU or the board/processor.

Most of the ATX troubleshooting documents and books that I've read suggest you get out the multimeter and test the 12v, 5v, and 3.3v rails to see if they are within spec, but this is far too simplistic when it comes to a PSU that is rebooting. Invariably the PSU will measure perfect 12v, 5v and 3.3v when you measure with the multimeter, but then will still randomly reboot. I understand that if the voltage goes out of spec for a second, whether trigger by the motherboard or PSU, then the Power_Good causes a reset, but you have no way of knowing what triggered this..

The best option I've come up with at the moment is to use a junk mother board with the PSU and see if it reboots with a different motherboard/processor combination, but this is hardly scientific. Is there any better software/hardware way of checking this in place.

[Agent24]

Re: ATX restart troubleshooting.

Are you sure it's the PSU and not Windows crashing with BSOD and autorestart is turned on?

[CapLeaker]

Re: ATX restart troubleshooting.

What you mean on site? Remote site or some office? If it is a remote site, try a UPS. I have a remote site that has computer freezing issues. OS is Linux no GUI, so should be rock solid one would think. After lots of troubleshooting it was a power quality issue. Installed an Online UPS ( conditions the power all the time) and no more problems.

[stj]

Re: ATX restart troubleshooting.

start the machine and go into the bios.
then go to the system monitor section with the voltages listed.

2 things of interest.
1: does it sit there no problem without resetting.
2: are the voltages stable or going up&down?

[momaka]

Re: ATX restart troubleshooting.

The best option I've come up with at the moment is to use a junk mother board with the PSU and see if it reboots with a different motherboard/processor combination, but this is hardly scientific.

Exactly, this isn't all that useful.
This is the kind of problem you have to investigate on site or bring the hardware home and test carefully. No other way. Best bet is inspect both the motherboard and PSU for bad caps and any other anomalities.

[c_hegge]

Re: ATX restart troubleshooting.

start the machine and go into the bios.
then go to the system monitor section with the voltages listed.

2 things of interest.
1: does it sit there no problem without resetting.
2: are the voltages stable or going up&down?

It's common for BIOS voltage readings to fluctuate, even if the voltage is actually stable going by a DMM. BIOS voltage readings should never be taken seriously or ever used in any form of troubleshooting.

The first thing I would try is Agent24's suggestion of disabling the Automatic restart after system failure option and seeing if the symptom changes from a reboot to a BSOD.