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My computer turns itself off randomly

By BigGooz ยท 16 replies
Feb 25, 2008
  1. I know there is a topic that addresses this already, but I have some computer-specific questions related to the procedure/advice that is given in the other thread. I have a IBM ThinkCentre 3.0Ghz machine that is randomly shutting itself off. It appears to be an overheating issue. The other post recommends checking the fans. I see two fans in there (they both work), but does anyone know how many fans there are in this machine (it's a tower). Is there a hidden fan that isn't working or is it just the two I can see? Second, if the heatsink has a thermal pad, do I still need to apply a new layer of thermal paste? Third, what temperature should a computer run at? The other post included a link to a diagnostic tool, but I don't have any benchmark for comparing my computer. Also, if the computer shuts down when it gets hot, how can I use the tool?

    Thanks for your help!
  2. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    If you want answers to "computer-specific questions" you have to be specific about your computer ;). Give us a model number or something to go on.

    I would assume you have at least one fan as a rear exhaust, a fan on your CPU's heatsink and then probably a fan inside your PSU.

    If the heatsink has a thermal pad on it, you don't want to add thermal paste on top of the pad. It's one or the other.

    There are various components within the computer and they all pretty much have a different maximum thermal specifications. Your CPU's maximum temperature is probably somewhere between 149F and 158F (65C and 70C). Look in your BIOS for a temperature reading on your CPU among other components.
  3. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly

    Do you mean that if I just leave the computer sitting there after it has shut down, it will turn back on after 5-10 minutes? When the computer does its "I'm turning myself off in the middle of a process" routine, the mouse, keyboard, harddrive, all that junk turn off, but the power light remains on. Will it restart after it cools down? Also, when I try to restart the computer, it will get to the desktop, then shut down. It does get by the BIOS and loadup screens, though. Is this normal for an overheating issue? Finally, what kind of issues could it be with RAM? Are there any tests/diagnostic tools to check?

  4. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    When you start your PC head into the BIOS and watch the temperatures of your devices.

    Yes, there is a great diagnostic tool for testing memory called Memtest86.
  5. Tedster

    Tedster Techspot old timer..... Posts: 5,746   +14

    generally caused by 1 of 2 issues:

    1. overheating

    2. bad or failing psu
  6. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly

    OK, so I ran SpeedFan to check my system temps and it came back with a couple disturbing things that I would like clarified. First off, it says that Fan 3 is operating at 0 RPM. Now, is this because Fan3 is broken or is it that Fan3 does not exist? Unfortunately, I think it is the former, as I can see 2 fans, neither of which are in the PSU. Second, the RPMs for the first 2 fans are 3400 and 1800, respectively. Appropriate? Third, here are the temps it gives:

    Remote 1: 40C
    Ambient: 35C
    Remote 2: 38C
    Remote 3 47C
    HD0: 0C
    Temp1: 57C (this one has a flame beside it)

    It looks like Temp1 is too hot. What is Temp1? When I click the Configure button, it tells me that Temp1 is at Sensor Temp1 and Chip ACPI. I don't know what this means. Please help.

  7. BigGooz

    BigGooz TS Rookie Topic Starter

    computer turns off randomly

    So I took out the power supply to check the fan (wow, what a pain!) and the fan is indeed broken. So what's my next step? Have I jumped to an incorrect conclusion?

  8. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    Eh, yeah I wouldn't open the PSU if I were you. If the fan is broken you can bring it to someone to have it serviced, however, it's probably going to cost more than it would to just buy a new one all together.

    In order for us to tell you what to replace it with, we will need (as I requested earlier) to know what model your PC is or a semi-detailed list of your system specifications.
  9. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    I would not trust a 500W PSU in my system if it were $16-$20. In fact, I'd pay not to have it in my system. There is much more to a PSU than the wattage output.
  10. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly

    Hey all,

    Thanks so much for your responses! I am at work right now, so I can't give you the exact specs on the computer. When I can post those, I will, but what is the pertinent information that you would need?

    Let me take you guys through what I did, so we are all on (nearly) the same page. I uscrewed the PSU case from the back, so that I could peek through the cage on the PSU to see if the fan was working. I did unscrew the case also, but I couldn't get it fully open. No matter; the fan was the only thing I wanted to check. So, in response to mrghost, I didn't see any cracks or anything (as I couldn't actually get into the case). All I saw was that, when I turned the computer on, the fan in the PSU didn't turn. That's how I came to my conclusion.

    That said, I also want to check the CPU/heatsink area to see if the thermal pad needs cleaning. However, I couldn't get the heatsink off. It is connected by two screws, but those screws have extensions that go down into their holes and prevent it from being opened. What do I do? Or, given the SpeedFan data, do I just conclude that it is the PSU and fix it? Does anybody know how to interpret those findings?

    Again, thanks for all your help, guys.
  11. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    I wouldn't trust Speedfan's readings personally. I have always had poor luck with that program, though, some will claim otherwise. I would do as I suggested initially and boot into the BIOS and check the CPU temperatures there (especially before going through the trouble of replacing the thermal compound).

    If the PSU fan isn't working, I'd say it's safe to assume that is your problem (or, at least one of them).
  12. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly

    Hey Zenosincks,

    I don't usually mess around in the BIOS. What is the procedure for checking the CPU temps in there? Also, when I first boot up the computer and go into the BIOS, how relevant will the temperature readings in there be, since the computer hasn't had a chance to warm up to meltdown state yet? Also, what should I be looking for when I get in there? What kind of readings would be a problem?

    Thanks again!
  13. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    When you first turn on your PC you'll see a quick splash screen or POST results. On that screen should be a message that say something along the lines of:

    Enter Setup F1
    Enter Setup F2
    Enter Setup Del

    Tap the appropriate key and you'll be presented with a menu of nifty little options. Look for an "Advanced" section, maybe "Hardware Monitoring" or something within the "Advanced" section. If that isn't there just roam around for a bit and use common sense, you'll find it.

    The CPU is under load during the booting process/while in the BIOS as far as I'm aware. Maybe not 100% load but it's doing something never-the-less.

    Copy/Paste from my earlier post: Your CPU's maximum temperature is probably somewhere between 149F and 158F (65C and 70C). So, anything that looks as if it's near the maximum temperature (within 10F-15F) and consistently climbing might be suspicious.
  14. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly


    OK, according to SpeedFan, I am operating at 65C right now, so I'm going to keep this quick. I poked all through the BIOS and found nothing related to temperature. I am so stinking frustrated right now! I looked in the Advanced Tab, Hardware Tab, under System specs, everywhere. Nothing. I made two changes, though. First, I set fans to "On", so they are always on, so I could check the fan in the PSU. Still nothing. Second, I disabled the Sleep mode function in there. That's the only useful things I saw. Still have no clue. But, as promised, here are my system specs

    IBM ThinkCentre minitower
    3.00 GHz P4
    512 MB RAM (yes, I know I need more)
    120GB HD
    Win XP Pro w/ SP2 and all updates
    333MHz bus, I think

    The PSU itself is a LiteOn with Model # PS-5022-3M. It has DC output of 230W, input of 100-127V @ 6A or 200-240V @ 3A. It looks like it has 3 output rails (3.3V, 5V, 12V) where the combined power on the 3 and 5 is not to exceed 100W and the total power is not to exceed 228W.

    OK, I'm pushing my luck. Thanks for the help.
  15. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    Eh, I get the feeling that your PSU is a custom OEM form factor. Could be wrong, but I'll look around for a bit. You might have to buy a replacement through them or snag one off Ebay...


    Everything seems to point in that direction as I figured. I could always be wrong, but, I'd say your best bet (if you're going to replace the PSU) is to just buy one from Ebay. Here is one on Ebay for $24.99 plus shipping of course.

    Your CPU temperatures are indeed very high if they are at 65C.
  16. BigGooz

    BigGooz TS Rookie Topic Starter

    computer shuts off randomly

    Hi Zenosincks,

    Thanks for looking into the PSU for me. I have a question for you, though. My current PSU is only 230W, which means that I can't use any sort of reasonable graphics card (actually, right now, I am devoting actual RAM for graphics). For this reason, I do not want to buy the same power source. Now, I keep my computer case open generally, since I like tinkering in there and cleaning it out, so my question is this: is it important to actually mount the PSU or can I just leave it unmounted, on the base of the case? Is there any danger to doing this? Will the fan cool properly if not mounted? And so on and so forth. I know it's a weird question, but I'd appreciate your (and anyone else who is reading this thread) opinion.

  17. Matthew

    Matthew TS Evangelist Posts: 5,270   +104

    I can't imagine not mounting the PSU inside your case would be an issue, make sure it's very stable outside of the case though.

    I you might want to spend some time comparing connectors and voltages. There is more to a proprietary PSU than the actual shape of it. If your PSU is an OEM's design, your motherboard might require some non-standard voltages or connectors. Make sure you compare the old/new PSU extensively before hooking it up to your machine.
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