Random computer shutowns

dawza

Senior member
Dec 31, 2005
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Not quite sure where this would best be posted. . .

I built a system for my parents about six months ago. Specs as follows:

Biostar 6100 T-Force Socket 754
Sempron 2800+ Palmero (with TT Silent Boost HSF)
Mushkin Value 2x512mb
Fortron AX-400PN
Leadtek 6200TC PCIe
WD Caviar 80GB
Lite-On DVD-RW
Audigy (original, more for Firewire than anything else)
XP Pro SP2
All drivers up to date at time of build; did not install NV Firewall or IDE drivers.


I tested the system for about one week before sending it home. Ran all of the normal stress tests (Prime 95, RTHDRIBL, etc), and everything was OK. Temps were great (<40C under full load), and the system never showed any signs of instability. The memory passed over 8 hours of prime in two systems.

All specs are at stock; no overclocking.

The actual build went without any hitches save one: when I first booted up, there was no power. The fans spun up for a second, the mobo LED diagnostic lights went on, but that was all. I went in and touched a 4-pin molex connecting to a fan and then everything worked. I assumed that this was some strange one-time glitch, and let it pass. This then happened again a few days later, which I likewise resolved by messing around with the 4-pin molex connectors. All was well after that last hiccup.

Yesterday, I learned that the system had been acting up in the past month, where it would randomly shut down, sometimes while surfing, or when just using Office applications. I did not get any details with respect to whether the mobo was receiving any power at all, although I intend to call tonight to get the specifics.

I will be flying home shortly and intend to resolve this issue. However, I am not sure where to begin troubleshooting. It would be simple enough to purchase a new PSU and have it shipped home so that I could test it out, but I would hate to spend the time and money rewiring the system if it was not a PSU issue. I currently suspect one of the following:

1. PSU
2. CPU fan running too slow (was spinning at 800RPM normally, but that had never been an issue even in the winter); not sure if I disabled auto shutdown for a stopped/too slow CPU fan in BIOS- but would this not cause rapid shutdown?
3. Loose connector (can a loose molex connnection even cause this?)
4. Mobo (hopefully not)

The system should be virus free; they are using DSL, and I have them on limited accounts, with Sygate firewall running (mainly to control apps from phoning home) as well as Avast AV.

I should mention that the area is somewhat prone to short power losses; however, the shutdowns did not seem to coincide with blackouts; are PCs more sensitive to short power outages that do not even faze alarm clocks? The system is surge protected, although no UPS.

Any tips? I am leaning towards #3, because it seems to have been an issue before, but I do not know if such a thing could result in random power loss.

All help would be appreciated.

 

pkme2

Diamond Member
Sep 30, 2005
3,896
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By the way, what's your PSU?
It hard to diagnose from afar but here goes.
First, switch out PSU and use another to test system.
I make a point of keeping a spare PSU around for testing purposes.
Take the rig to a local neighborhood shop, if you don't have a multimeter handy.

 

gamefreakgcb

Platinum Member
Sep 2, 2004
2,354
0
76
this started happening to me, turns out the Heatsink Fan was not working, since you mentioned very low RPM, that could be an issue.