Detective work: diagnosing a bad Motherboard or PSU

[john5246]

Symptoms:

Computer shuts down unexpectedly. Tries to reboot, does not POST, shutting off the PSU from the back for a while or reseating RAM helps, computer runs for hours at a time but other days seems to only last 10mins or some other random amount of time before shutting down automatically.



Troubleshooting:



1. Reseated all components, cleaned CPU, reapplied thermal paste and heatsink, compressed air to completely clean entire computer including PSU with PSU cover off


2. Disconnected all extra components, ran only 1 HDD, MOBO, Video card, and CPU, computer shuts down


3. Removed each stick of RAM, ran one stick at a time, same problem, computer shuts down (in addition to 1 above)


4. Booted into BIOS, left computer on the BIOS screen, shutdown after 5mins automatically (in addition to 1)


5. Used SpeedFan to check CPU temps, CPU operating at 35C idle, 45C load, GPU temps ok as well








What could be the problem here? I don't want to buy a new PSU if that's not the problem, I won't be able to use a spare PSU until I make a new build which won't be for a while. I can't run memtest86 because I can't find a floppy disk lol, or a spare cd, and since I ran one stick at a time I don't think that the problem, each HDD has windows 7 and I ran each one seperatly so I don't think that's it either. Based on the symptoms and you're experiences what do you guys think the problem is?

Also i don't want to risk my good PSU from my new build to test in the old system, it's a pain to take apart. I do have a voltmeter, but am scared to test the PSU. Any ideas?


Intel Board
Pentium 4 1.8Ghz
1.5 GB of RAM
FX 5000 series Nvidia GPU (AGP 4x :lol: )
bought in 2002 (VPR matrix from Best Buy)

 

[1965ohio]

What is the exact model of your motherboard? Can you see any identifying markings? Also what type CPU socket is this P4? 423 or 478? If you have the 478 with DDR memory, what is the exact speed and type? I just want to narrow down the makes and models of these parts in case of known issues.

What is the make and model of your PSU? Usually in this kind of situation, the PSU failing would be my first assumption if I could verify the RAM with memtest86+ I would be more certain in helping you.

Since you are using Windows 7, did you run the built-in memory diagnostic tool? If not, this is how you do it. Open the control panel and click to view by small icons. Then click on administrative tools... then double click on the Windows Memory Diagnostic shortcut. It will ask you if you want to restart and run the test now... select yes. When the computer restarts, you will see a blue and yellow screen that will test your memory. Since you have an older PC, it may take a while to complete. Don't interrupt it and let it finish. It will tell you if it finds any errors... if you have other work to do, let it finish and restart itself. It will give you a summary the next time Windows starts.

If you have no errors, it still doesn't mean 100% pass because the Windows diagnostic isn't as good as the others... but if it had any errors at all, re-run the test with each stick one by one until you find the offending stick.

If you cannot find any errors in the memory, I will also ask you if there was any drivers you updated recently before this happened... but considering your hardware, I don't think there has been any updates for some time. So I will still lean towards the PSU. If your budget allows, I would recommend getting a new PSU now, you can carry it over to your next build... and it will answer your questions most quickly. But PSUs do go bad and have these exact symptoms.

You can try to download something along the lines of system monitoring software and check the voltages. Keep it open all the time and watch the different readings on idle and under a load and see if one of them fluctuates too much... then the PSU is definitely the culprit.

http://www.softpedia.com/get/System/System-Info/Motherboard-Monitor.shtml

 

[john5246]

What is the exact model of your motherboard? Can you see any identifying markings? Also what type CPU socket is this P4? 423 or 478? If you have the 478 with DDR memory, what is the exact speed and type? I just want to narrow down the makes and models of these parts in case of known issues.

What is the make and model of your PSU? Usually in this kind of situation, the PSU failing would be my first assumption if I could verify the RAM with memtest86+ I would be more certain in helping you.

Since you are using Windows 7, did you run the built-in memory diagnostic tool? If not, this is how you do it. Open the control panel and click to view by small icons. Then click on administrative tools... then double click on the Windows Memory Diagnostic shortcut. It will ask you if you want to restart and run the test now... select yes. When the computer restarts, you will see a blue and yellow screen that will test your memory. Since you have an older PC, it may take a while to complete. Don't interrupt it and let it finish. It will tell you if it finds any errors... if you have other work to do, let it finish and restart itself. It will give you a summary the next time Windows starts.

If you have no errors, it still doesn't mean 100% pass because the Windows diagnostic isn't as good as the others... but if it had any errors at all, re-run the test with each stick one by one until you find the offending stick.

If you cannot find any errors in the memory, I will also ask you if there was any drivers you updated recently before this happened... but considering your hardware, I don't think there has been any updates for some time. So I will still lean towards the PSU. If your budget allows, I would recommend getting a new PSU now, you can carry it over to your next build... and it will answer your questions most quickly. But PSUs do go bad and have these exact symptoms.

You can try to download something along the lines of system monitoring software and check the voltages. Keep it open all the time and watch the different readings on idle and under a load and see if one of them fluctuates too much... then the PSU is definitely the culprit.

http://www.softpedia.com/get/System/System-Info/Motherboard-Monitor.shtml

That's what I was trying to do with HWMonitor, but it will only detect my HDD not tell me about the voltages, on my new build it works fine.

Like I said, I tried each stick or RAM one at at time and the problem persisted. I can try to run the memtest. The problem is I don't want to waste money on a new PSU because the kind I want is rather expensive.

I want a 750-watt modular power supply to put in my CURRENT build and the 600-watt PSU I have now will go into the old computer. The problem is that PSU costs about $119

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4558896&CatId=2533


I don't want to spend, $30/$40/$50 on a cheap PSU and then have to buy ANOTHER PSU in the future to do crossfire/SLI with since the 600w PSU I have now might not handle it.

The other thing is I just spent $89 ($69 if they ever send the rebate) a few mins ago buying 8GB of Corsair XMS3 Series DDR3 RAM for my current build. And the truth is I'm wasting money, I currently have 2GB of corsair ram and I get by just fine on it. Though I have the money I don't like to waste it, I visit newegg frequently and only pick up the best deals. It took me 1year to by a CPU cooler even though it was only $30, and the only reason I bought it is because they had a $15 rebate on it (which I still haven't received), it was the coolermaster Hyper 212+ heatsink =)



I could take this PSU out and use it to test but I don't want to damage it. I think I might try using the multimeter and risk getting shocked rather than pull all these wires out of my current system.

 

[1965ohio]

If your memory is good and your PSU is bad, not much you can do but replace it now. If you have no way to truly test the RAM and the MB monitor isn't showing your reference voltage, then perhaps you have a bad MB.