Dead mobo?

Discussion in 'General Hardware' started by Glaanieboy, Jan 21, 2005.

  1. Glaanieboy

    Glaanieboy Moderator

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    I am trying to fix a computer for a colleague of mine, I am having all kinds of problems with it. Let me start with the beginning:
    My colleague told me he had a computer (Asus A7V mobo, AMD Athlon 900 MHz, 512 MB SD-RAM) from his parents-in-law which has all kinds of problems with starting up. He got blue screens at random times, the computer occasionally didn't start up at all etc. He took a peek in the BIOS hardware monitor to see what kinds of temperatures the system generated. Well, it turned out the CPU was running at 90+ degrees Celcius (that is almost the boiling point of water for you who use Fahrenheit), so there was something seriously wrong. He gently vacuumed the inside of the case to get rid of all the dust that has been accumulated over the years, but that had no effect.
    When he brought it to me the day before yesterday, I took a peek at the CPU fan, which was clogged up with burned up dust (judging from the bad smell and brownish color). The fan was literarely stuck, so I had to jank it loose and I tried to rub all the dust off with a dry cloth and a vacuumcleaner.
    When I had cleaned off must dust from the fan, I placed it back onto the CPU, attached the cables back in the mobo and hit the power switch. I heard fans, harddrives and a cd-rom (I forgot to took out of the player) spinning up and waited for the POST screens to appear on the monitor. Nothing, just nothing. I checked the CPU, it was very hot and when I looked at the fan, I knew why, the fan didn't spin at all. It just stood still, waiting for ... something. I took the fan + heatsink out and tried connecting it to another computer (Intel) and it immediately worked liked normal. So there is nothing wrong with the fan. I brought in a spare fan, just in case, but again, nothing on the AMD, but it worked on the Intel.
    Time constraints forced me to take the computer home, I would have a look today. Today I disconnected all drives, cards etc (including RAM and videocard) except the CPU and the heatsink + fan combination. I plugged in the mobo-power connector, powered it up. The PSU-fan turned on, the harddrive turned on, the standby-light on the mobo was on, except for the CPU-fan. I tried connecting the plug to the CPU fan to the chassis-fan connector on the mobo, but still nothing.
    This little :)rolleyes: ) story leads to one question: What can I do further to test the system? I don't have a spare mobo and CPU for testing, I only have the stuff which was already in the case. I reset everything to default (all jumpers and dipswitches. Also the BIOS, which I reset to default before the computer meltdown), so there just can't be something wrong in the settings. I am afraid the CPU is fried, but there can also just a simple setting I missed. The CPU itself looks OK (no burn marks for as far as I can see), but the socket does have little black burn marks.
     
  2. Electronic Punk

    Electronic Punk Administrator Staff Member Political User Folding Team

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    MAy be worth trying to power the cpu fan by alternate means and seeing if this increases system stability. I would definatly agree that the crashes are caused by the CPU temp as I think mine used to crash at those temperatures (I think SETI @ Home caused it)
     
  3. lancer

    lancer There is no answer! Political User Folding Team

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    I think, you'll find the mobo cpu fan connector is dead. This probably happened due to the amount of dust, causing the fan to slow and eventually stop, which in turn probably overloaded the circuitry around the fan connector (i would also assume with all the black marks that the dust got superheated (lucky there was no fire) and melted to the circuitry attributing more to the ciruit failure). Theres nothing you can do, but get him to buy a new mobo, and probably a new cpu whilst he is at it.
     
  4. Dublex

    Dublex Quazatron R6 droid

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    lancer's verdict sounds likely to me as well... things can get pretty bad when they overheat, your friend is lucky the who motherboard didn't fry or catch fire - a testament to certain motherboard builds.
     
  5. Glaanieboy

    Glaanieboy Moderator

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    The fan is fine. I just tested it on my PIII machine and it works OK. Somehow the mobo isn't giving power to any of the fan connectors. I think the CPU or the mainboard may be fried, but its up to him to make the decision to bring it to a shop.
     
  6. lancer

    lancer There is no answer! Political User Folding Team

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    why would he get someone to repair it, sounds like a piece of **** to me, it'll cost twice as much to fix as it would to buy a new board and cpu.
     
  7. Dublex

    Dublex Quazatron R6 droid

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    Does your friend know exactly how long the blue screens and other problems have been happening for? that way you could possibly work out if there was damage caused to the MB - but at this stage it sounds as though a new board is in order (unless you are an expert at rewiring mb fan connectors)
     
  8. Glaanieboy

    Glaanieboy Moderator

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    I'll leave it up to him. I've told him what I found and he also said a new computer might be in order. I bring it back to him tomorrow and it's up to him what he wants to do with it.
     
  9. bush dogg

    bush dogg OSNN Senior Addict Political User

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    What about trying something like this connector to run the fan from the power supply and go from there?

    Tigerdirect
     
  10. Glaanieboy

    Glaanieboy Moderator

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    I don't think that would matter much. But, as I said, I'll leave it up to him. And Tigerdirect won't do any good, as I am from the Netherlands :p But I get the message :p