TechSpot

Computer won't power up

By Hercules1946
Aug 23, 2009
  1. The computer I built in 2002, running XP Home started to give me a lot of problems and after trying verything I could to solve them, I gave and started looking for a new mainboard.
    After talking with an upgrade company, they told me that they could supply a new mainboard that was compatible with my Gigabyte GA-7VRXP so I ordered it.
    I fitted it, along with new memory and an empty formated hard drive to re-install XP.

    When I press power on, it starts up normally for about 5 - 6 seconds and then powers off. This is too quick for anything to appear on the monitor. Ive checked and rechecked the front panel connectors which are mostly plugged into one 9 pin panel and I can't find the cause.

    Do you have any idea what might be causing this ?

    The new board is an ASRock K7S41GX.

    Im really depressed about this. Ive built 3 computers before without any problems.
     
  2. nileshsatpute

    nileshsatpute TS Rookie

    This problem may occurs if your HDD is short.
     
  3. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

    Computer Wont Power up

    Hello
    Im not sure what is meant by a short HDD, but is was fine when I reformatted it whilst the old board was in place. Effectively its like a newly built PC with an empty HDD ready for installing Windows.
     
  4. gbhall

    gbhall TechSpot Chancellor Posts: 2,361   +52

    With no OS on the HDD you need to set the boot order in the bios so that the CD/DVD drive is first. To get into the bios, you press some key or other immediately after switching on, but you should see some bios info for a few seconds - including the important info as to which key you need to press to get into the bios.

    As you apparently do not get that initiial power-on bios info, something is clearly wrong. You must check all connections carefully - one may be reversed, or the memory may be unseated, or careless handling of the motherboard/memory/cpu may have caused failure due to static discharge. The omens are not good.

    Best I can suggest is disconnect the HDD and see if you get a bios screen. If HDD and CD/DVD are on the same connector ribbon, you need to check you have them the right way round, and have primary/secondary shorting pins correct. Exactly which device goes where on a ribbon depends on the type of ribbon. You will need to research that.
     
  5. RICK0140

    RICK0140 TS Rookie

    it may be the cpu, if you have refitted a new board and then replaced a heat sink and fan on it , but you may not of used cooling gel on the cpu, this will cause it to over heat straight away and turn off, this happened to me some time ago..just another possability,
     
  6. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

    Computer Wont power up

    Hello
    Ive tried disconnecting both the HDD and the CD, which are separately cabled to IDE1 and IDE2. Everything has been handled carefully and ive checked all the connections. I applied paste between the CPU and the heatsink.

    As Im only getting 5-6 seconds of activity before it powers off its not possible to make any changes to the BIOS as the monitor isn't activated. The only case connector I was uncertain about was Reset, where in the manual an illustration showed one of its pins as 'dummy'. Also, both wires are grey, but I tried both ways round. The other illustration was quite clear in showing the correct pins for the reset cable.

    One thought.. When the old board was in operation, by pressing and holding in the power button you could power off the system after a few seconds. This is effectively whats happening when i power on. I wondering if I might have a faulty power switch. Is there any way to test this (say by bypassing the switch) ?
     
  7. RICK0140

    RICK0140 TS Rookie

    to be honest m8, i have a computer upstairs doing the same thing, it starts loading windows then just turns off, not sure what it is, but i think my proccessor is broke, im gonna take it to the shop tomorrow and i will let you know what they say, you may have same problem,,
     
  8. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

    Hi Rick
    Thanks for that and let me know what they say. If you have got a problem with the processor, the it might be the BIOS thats shutting down the system because a critical temperature has been reached. Also, it might be worth checking in your BIOS to make sure that critical temperature is set at a sensible level.

    I think in my case Ive just bought a dodgy replacement board, after carrying out all the tests suggested by the supplier we agreed that I would return it to them.
     
  9. AndrestheBean

    AndrestheBean TS Rookie Posts: 217

    return it and get a better board of newegg.

    what are your current system specs?
     
  10. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

  11. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

    Computer wont power up

    Hello
    I decided to check the voltages on my power supply and I got some degree of variation. I was wondering if these are within tolerance or would be enough to disrupt normal operation. My readings are in brackets:

    3.3V (3.4V) ; -12V (-11.09V) ; -5V (-4.96V) ; 5V (5.21V) ;12V (12.32V
     
     
  12. Gravity

    Gravity TS Rookie

    Maybe you can check ur RAM if it is correctly plugged in. Remove the RAM, clean it a little plug it back agn
     
  13. gbhall

    gbhall TechSpot Chancellor Posts: 2,361   +52

    Your 12V rail seems more than dodgy. On the other post you had -11.8v now -11.1V Such a large variation is not good at all. If this is a PSU that has been in use since 2002, well..... worth changing it surely?
     
  14. easethepain

    easethepain TS Rookie Posts: 17

    Hi

    My advice to find out if its the board or the soft power off switch on the board or overheating is
    to disconnect everthing except the memory and graphics card short the pins on the board that normally is used for the power on switch with a magnetic screwdriver this will cause the board to fire up go straight in the bios if you can if it does power up and then power off again after a short time it will be either a faulty board or a configuration error in the bios.

    let us know.. your findings

    EasethePain
     
  15. maestromasada

    maestromasada TS Rookie Posts: 97

    If you only had Ubuntu...
    .. you could reboot your computer from the Ubuntu-cd and load the OS without the need of a hard drive.
    Then, if the drivers are loaded ok, go to http://support.wdc.com/product/download.asp?lang=en and download the Data LIfeguard Diagnostic for DOS on a floppy, then reboot your computer and check the hard drive with the Lifeguard utility. Sure it will tell you if it is about to go for good.
     
  16. maestromasada

    maestromasada TS Rookie Posts: 97

    Gosh! I realise I posted my reply on the wrong thread. Please ignore it!
     
  17. Hercules1946

    Hercules1946 TS Rookie Topic Starter Posts: 26

    cant Boot the computer

    Hello Everyone
    Thanks for your help and advice. I found a number of old articles about my old board which led to a solution. Apparently the Gigabyte GA-7vrxp has a kind of fault that can cause the CPU to be starved of voltage by the graphics card, causing it to lock up or blue screen.
    This had been resolved by increasing the core voltage in the BIOS.

    When I read this, I refitted the old 7vrxp board and upped the core voltage. Its now working normally again!
     
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