Computer shuts downs

[Ark]

Having problems with old computer - I need to keep it alive for a couple more months at least:

P3-733 with MSI 815E board: sudennly stared lockups during minor usage. It started once a day about month ago, now it happens every 10 minutes:
Troublesjooting done so far:
CPU temp shows as 73 DEG C but CPU and heatsink are cold - sensor bad?
Removed and relaced memory,
Disconnected 80GB harddrive, 160GB only (can this be a BIOS problem?)
Bumped CPU voltage a little,
Replaced mouse and keyboard.
Did virus and adaware scan, uninstalled all unused programs.

When computer locks, it seems to be still working: onscreen TV still on, but no response to keyboard, mouse and network.

Any other ideas?

 

[mechBgon]

You're off to a good start there. From past experience, my suspicions fall on either the motherboard or power supply getting ready to kick the bucket.

If you want to do a little more troubleshooting, you might try downloading and running Memtest86 and see what happens. If the system doesn't keep locking up while running Memtest86 from a bootable floppy, then perhaps it's a Windows problem. If it comes up with memory errors, perhaps the motherboard or memory are failing. If the system locks up anyway, then perhaps the power supply or motherboard are failing.

If the power supply remains as one of the suspects, then you might try a different one if you have one, or pick up a new one if you feel it's worth the gamble. Antec SL300 would be a good one that should be easy to find.

 

[johnjkr1]

You might also want to try reseating the CPU heatsink. It should get at least somewhat warm. Also, does it lock up just sitting in the bios? If not, then you "might" have a windows issue.

 

[Ark]

Thanks for replies:

I re-seated heatsink this morning as well as CPU itself then I saw high temps:
heatsink it is warm, but not hot (73C).
I am pretty sure temp CPU sensor is not working, where is located?
On MB under CPU or inside of CPU?

I am running memtest86 from CD while I am typing this on my laptop.

I also suspect PS or MB. Most likely MB. I don't think it is a Windows.
I will grab a new PS tomorrow at Microcenter.

I also suspect thet it may be BIOS support for 160GB - I know there is a limitation, but with partition 80GB, WinXP with all srvice packs and Intel app accelerator it should work. at least it was working for over 2 months.
I also have a working image about 2 months old on 80GB drive, I may just swap drives if it passes memtest86.

I'll keep you posted.

 

[mechBgon]

Originally posted by: Ark
Thanks for replies:

I re-seated heatsink this morning as well as CPU itself then I saw high temps:
heatsink it is warm, but not hot (73C).
I am pretty sure temp CPU sensor is not working, where is located?
On MB under CPU or inside of CPU?

I am running memtest86 from CD while I am typing this on my laptop.

I also suspect PS or MB. Most likely MB. I don't think it is a Windows.
I will grab a new PS tomorrow at Microcenter.

I also suspect thet it may be BIOS support for 160GB - I know there is a limitation, but with partition 80GB, WinXP with all srvice packs and Intel app accelerator it should work. at least it was working for over 2 months.
I also have a working image about 2 months old on 80GB drive, I may just swap drives if it passes memtest86.

I'll keep you posted.

Since you re-seated the heatsink, I have some follow-up questions:

1) is it oriented like this (yes = )

2) if it had a melt-to-fit phase-change thermal patch on it, did you scrape it all off and use high-quality thermal grease in its place? Phase-change patches are a one-use-only product.

 

[Ark]

Question 1 YES - it will not fit opposite -I saw this
Question 2 NO :disgust: I don't have thermal grese today, so I thought old one is better than nothing.
I will get new tomorrow.

Memtest86 failed at about 60% - so it is not a HD or Windows.

So we have 3 things: MB, PS, external noise may be via network (unlikely).
I am not taking memory out of picture also, but I did replaced it.
Next I will remove all cards and disconnect all drives except CDROM - I need it to run memetest

 

[mechBgon]

FYI, if the 73C temperature reading is correct, be aware that's extremely hot for a Pentium3 with a Coppermine core. I'd hold off on anything until you've got your thermal grease.

 

[Ark]

One more test for today: I will put 128MB memry stick from my wifes PC and try.
2nd memtest frose at the same place 66% so it may be bad memory.

 

[Ark]

Ok, got thermal grease from my buddy, scraped old stuff, put new.
memtest86: locks up computer at the same place at 66% exact same location with 2 different memory stcks running in different slots.
So it is not memory or PS

CPU or MB?

Can this be cache memory?

I will try to disable cache for memtest86 to see. L1 or L2?

 

[Ark]

Disabled L2 cache: passed all memory tests.
Restared Windows see if it works.
It will be poor performance without L2 cache... But still better than crashes.

 

[Ark]

Thanks everyone who helped me here over email and PM.

Biggest thanks to mechBgon: you were really close to point to the problem.

Yes heatsink was installed with correct notch orientation.
Yes new thermal grease helped a little.

But the problem was that I did not install a heatisnk spring clamp correctly:
This is assymetrical clamp and middle point must be exact above the CPU pad.
I put it 180 deg off when I did cleaning about a month ago and clamp was actually pushing heatsink away from CPU pad.

Just simple change of clamp direction lowerd temp down to 46-51 DEG C from 73C+ with heavy load.

Learned the lesson - heatsink is most important PC part.

Thanks againg to everyone.