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My PC powers on but that's about all!

Discussion in 'PC Hardware' started by nandrews, Oct 8, 2009.

  1. nandrews

    nandrews Guest

    I have a PC which fails to boot (fails to do much at all except spin
    the fans and discs!)
    Occasionaly when I turn it on it makes a tone The single tone lasts
    about 10 seconds with about a 3 second pause, then 10/3, 10/3 etc.
    etc. I can't find that decoded anywhere tho' I suspect it may point to
    video or memory problems,
    I have swapped the video card for a good one with no change. I have
    swapped the memory cards around with no change.

    Can anyone advise what this tone might mean?


    Thanks
    Nigel
     
    nandrews, Oct 8, 2009
    #1
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  2. How about a bit more detail? "a PC" could be a 1978 8086 running at a
    blistering 5mHz, or last week's model that can count every grain of sand
    on Earth in 1/2 a second.
     
    MasterBlaster, Oct 9, 2009
    #2
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  3. nandrews

    nandrews Guest

    OK OK!

    It's a Pentium P4 with 2GB memory.
    But what more, that is relevent, would help diagnose this problem.
    Afterall it is at it's very basic level that it is not working. The OS
    is not involved, nor any peripherals.

    Please advise

    Nigel
     
    nandrews, Oct 9, 2009
    #3
  4. Ok so the board doesn't have a backup bios like newer boards. What
    you need to do *before* unplugging cards etc and *after* you discharge
    your static electricity against the bare metal part of the case, is
    unplug the computer from the wall and pull out the CMOS battery. It
    will be a thin disk battery in a round socket, friction held by a
    sprung prong. Just lever it out, remember its polarity, and leave it
    out for 10 minutes. Then, replace it, correct polarity.

    This will take your BIOS back to factory default. If you still get no
    screen, no boot at all, then its something electrical. It won't be
    your hard drive because you would still get a boot screen, I wouldn't
    have thought it was a PCI card because they are detected generally
    after BIOS. So, is your board dead or mostly dead? They are so
    complex perhaps you are getting throughput to the LED but everything
    else is dead? Do you hear hard drive spin up, or can you feel it? Are
    there any other lights on the board, eg, the LAN input or an onboard
    power led?

    Give me a few more facts please and we can sort this out. I get paid
    for this sort of thing, but only as a hobbyist.


    thang
     
    thang ornithorhynchus, Oct 11, 2009
    #4
  5. nandrews

    nandrews Guest

    Thang,

    Thank you for your reply (and those from others) but you have come
    closest to appreciating the situation and taking in the symptoms I
    have described so far.

    I will try the BIOS battery removal as you suggest.

    I have looked for an onboard LED but can't see one. However the case
    LEDs for power and disk, that are wired from the mobo, are lighted
    (the power light is continuous and the disk is steady for about 10
    seconds and then out).

    The hard disk(s), consistent with the case LED, spins and chatters for
    a few seconds.

    As I have described before the CPU fan runs along with the PSU fan.

    About 1 time in 10 when I power on the repeated long beep code sounds
    (10 secs on 3 secs off).

    I have swapped the memory cards about and removed each leaving the
    other inturn in each slot.

    I STILL have to check the PSU voltages and I must do that this
    monring!

    Thanks again
    Nigel
     
    nandrews, Oct 11, 2009
    #5
  6. nandrews

    nandrews Guest

    Thang,

    I have now tried those things. Removing the CMOS battery for a few
    mins and checking the PSU voltages.
    All the voltages are there and there was no change in the boot-up
    i.e., there was none!

    I have gone further and taken it to two repair shops.
    The first inserted a diagnostic card and that encouragingly made it
    boot up normally! But he wasn't able to read anything useful from the
    card. I wasn't confident in his diagnoses and took to another shop
    where they spent a while swapping out components, but with no success.
    So both said it must be a motherboard fault.

    Of course it should be possible to diagnose the fault on the board,
    but maybe the cost in time outweighs the cost of a new board.

    Any further info would be gratefully received.

    Nigel
    P.S. I assumed the diagnostic card was supplementary to the
    motherboard and would be able to diagnose the fault, but it seems it
    effectively replaces the motherboard (which is surprising seeing that
    it just sits on the bus) and so the fact it made the PC boot was to be
    expected.
     
    nandrews, Oct 17, 2009
    #6
  7. If it is an electronic fault, that is, the circuitry, you need a new
    mainboard. However, if you have access to another machine, and decent
    download speeds, get your hands on Hirens Boot cd which has many many
    BIOS, CMOS etc diagnostic pre-boot routines (assuming you can access
    your own BIOS so as to configure your bootup from CD before HD or
    floppy/usb). You may find a decent diagnostic which informs as to the
    fault.

    Have a look at the board. If you see a capacitor with froth on the
    top, the board is unserviceable (recent boards have japanese caps,
    which are very reliable). It may be cracked, check to see if any
    screws have impacted any circuitry. Have a look at the connectors
    from the power supply - jiggle them and ensure that they are snug.
    Look at your graphics card if it is PCI and make sure it is snug. Etc

    Let me know how you go.

    thang
     
    thang ornithorhynchus, Oct 18, 2009
    #7
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