[OT] PC Hardware Problem

I had the same problem. Starting a few weeks ago my computer started freezing up mainly after I would leave it(say in over night). It turned out that the heatsink compound was dried up... fixed that and it's been running fine ever since(about 2 weeks).

Of course it could potentially have been something else but that seems to have been the issue. What happened was the thermal compound was relatively dry and I guess wasn't making good enough contact and would eventually cause the thermal sensor to trip(most modern CPU's have a shutdown mode to prevent damage).

I was monitoring the temp too but since it always happened when I was off(except the last few times) I never knew what was going on and imagined it couldn't be overheating when I wasn't on it(since it was basically in idle) but after replacing the compound no issues at all.

Anyways, it's worth a look...

It could be the memory or PS... usually one of those is the issue(Which is why I figured it was my memory since I have a monster PS).

Check the BIOS settings, and if possible alter them (memory timing, CPU speed, etc.) to use more conservative settings. If the BIOS settings were not improper (overclocking) and the problem goes away, don't expect it to be a permanent fix as the faulty part is likely to continue to deteriorate until even the more conservative settings will not keep it stable.

The next thing I would do is buy/get one new memory module. Then, run on just that one for awhile. If the problem does not happen at all, one of your original memory modules is probably bad. Reintroducing them one by one should reveal the troublemaker.

You can use a hair dryer (watch your operating temps, don't over do the heat) and freeze spray on the CPU and main chips to see if one is thermally sensitive.

You can try pulling cards and see if one is causing problems on the power supply or bus, but I have not see cards cause problems like this often in practice (it usually shows up as problems related to the function of the card).

The next thing I would do is swap out the power supply.

What remains is problems with the onboard chips or electrolytic capacitors which probably means a new motherboard is in order. If you want a recommendation here, I've had good experiences from those from Tyan.

I have found that compiling a Linux kernel:

can present a more intensive test than many memory test routines, although I would still suggest you try them. IMHO, a machine should not be put into service until it can show that it can compile a kernel a few times after being fully warmed up (run for a couple hours before compiling).

BTW, I'm CCing this to sci.electronics.repair as that is a better place to ask this.

Cheers,

Mike Shell

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How old is the board? Bulging caps? Flaky power supplies mimic lots of othe problems,

G=B2

What did you use for heat sink compound? Just the usual white silicone goo like I may find in my 30-year-old tube? This has the magic melting elastomeric stuff that came with the CPU.

We've replaced the power supply, and drives, and played 'swap the memory' games -- still does it. The caps on the mobo look good, so either it's a bad cap that's not visibly bad, or it's a CPU fit issue.

If I have good heat sink compound I think I'll give that a go.

Sometimes the problem can be mechanically affected. You can try using an insulated (e.g., a plastic pencil with rubber eraser tip) rod to press around and tap the chips and a few places on the PCB. Sometimes there are bad solder joints that can show up this way and these often are affected by temperature as well.

A CPU substitution might be a good idea if you have another unit. Be sure and check the CPU voltage settings too.

Cheers,

Mike

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How many erratic CPUs have you ever run into? Personally I've worked around hundreds of PCs and when they go flaky it's most likely bad power from bad caps in power supplies and on the motherboard. Memory fails but much less often and processors even less often than memory. Look for caps and beware of ESR meters. Design engineers often parallel small value ceramics with the 'lytics that can fool ESR meters. Removing suspect caps and checking out of circuit. If the ESR meter says it's bad, it IS, if it says it's good, it might or might not be. If several identical caps on a board are bad while identical ones measure 'good', change them all and if it makes you feel better, check the removed ones after they're out but change them. You will be right >90% of the time.

BTW I had a mobo last year that the caps looked absolutely fine but measured terrible. I got to work on it after the IT guys tried the memory and CPU swap game with no luck. BUY GOOD CAPS !!! Beware of little brown mists near the caps which is acid leaking out. ALWAYS change those AND clean the acid off the board.

G=B2

I got roped into fixing a friends-friends TV. This was in days before DVR/VCR's. I get to their house and they are watching their favorite TV show on their small TV and it is upside down on a chair! It worked upside down but not right side up! This was a good sign as I knew I probably wouldn't need to do more than solder a loose part and I would be a hero!

I opened the back up and asked the wife for a small artists paintbrush and brushed it on the parts on the PC board until the problem reoccurred. Turned out to be cold solder on a coil or delay line widget.

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I agree, probably 85% of the time, it's a flaky power supply. That is if after you've cleaned all of the components thoroughly, it still fails. I've found on many of the newer(cheaper) supplies, the fan in the supply fails long before the caps. Probably the next most common issues that I've encountered are video card, ram, motherboard then hard drive. In that order. Although, the video card probably wouldn't cause a kernel panic. I did have one motherboard that had a video memory error, it finally became such an issue that it wouldn't even POST. Which sucks, because I could have used a video card instead if I could have booted without having to rewrite the bios.... anyhow off topic.

What does the system consist of?

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Oh, and I'd add CPU fan or bad thermal paste in the list between video card and ram... I've never actually had a flaky CPU. Cross my fingers.