1. This forum section is a read-only archive which contains old newsgroup posts. If you wish to post a query, please do so in one of our main forum sections (here). This way you will get a faster, better response from the members on Motherboard Point.

Weird sequence of events with multiple processors seemingly dying

Discussion in 'AMD Overclocking' started by SpellmanXP, Oct 11, 2004.

  1. SpellmanXP

    SpellmanXP Guest

    NF7-S mobo w/Mobile Athlon 2500 @ 2455Mhz (11x223)


    My CPU temp has always appeared in negative temperatures so I naturally
    assumed that the sensor was screwed up.

    Needing an idea of what the temp. is, I bought a secondhand Digital Doc. I
    managed to get one of the flat sensors wedged into the top of the heatsink,
    fairly near the base. I always added 10 degrees to this when guesstimating
    the cpu temp!

    Wanting a more accurate measure, I decided to try and slide two flat sensors
    PARTIALLY underneath the cpu whilst the lever was raised, then lower the
    lever and have them wedged in. I removed my motherboard and installed them
    so they weren't touching any pins.

    When I'd put everything back together again, the PC booted up but the
    monitor didn't come on. I realised I had a problem and instantly powered
    off. I removed the motherboard and the sensors, then tested everything
    again. This time it was ok. Before returning the motherboard to the case, I
    decided to take a close look at the mobo-based sensor under the cpu. When I
    looked closely at it, it seemed to be too far from the cpu itself. I bent it
    upwards so that it would touch the cpu - not thinking that this could cause
    any damage.

    When I turned the PC back on, the fans started and the HDD's began to
    spin-up but everything just cut out and stopped. The light on the mobo was
    on and didn't do anything so I tried again - same thing happened. Somehow
    forgetting that I'd made a significant change by moving the sensor, I tried
    a 2600 athlon. Same problem. Next up a 2000 athlon... nope, nothing
    happening.

    I took my processors over to my other PC (PC#2) and quickly removed the
    cover and first tried the mobile 2500. Exactly the same problem occured - it
    switched off after a few seconds. This repeated itself with the next two
    processors.

    I was absolutely gutted. I couldn't believe I'd wrecked 3 cpu's in about 5
    minutes.Amazingly, it was only now that I recalled having adjusted the
    sensor on my NF7. I bent back the sensor and installed the cpu but the
    problem was the same. Over the next 20 minutes I switched PSUs around, tried
    different cables and even turned off major appliances in the hope that there
    was some sort of overload going one. Out of nowhere, the idea came to cover
    the sensor with something. The obvious material seemed to be a piece of an
    anti-static bag . I cut a tiny square and covered the sensor. When I
    switched the pc on with the mobile athlon...success! I tested the 2000
    next - yay! Finally the 2600. That didn't work but I wasn't too bothered as
    it doesn't have a place in any PC I own right now. It was only now that I
    had connected up my PC speaker. All three produced a two-tone siren
    (overheating or out of specification voltages?)which stopped on the
    mobile2500 and 2000 but continued on the 2600 until I switched off.

    Having found a solution, I bent the sensor back and made sure the
    anti-static material was in place. The PC booted up fine and delivered a
    real temp. reading at last. Before putting the mobo back in the case, I
    again tested the 2000 in PC#2. Now, before all of this nonsense began, that
    athlon 2000 had been running on PC#2 without problems. I put it back in #2
    but it went back to the switching itself problem! How? Why? What??!?! There
    isn't a sensor on PC#2! I hadn't adjusted anything! It seemingly copied it's
    more impressive counterpart.

    Once I'd got the mobo back in the case and upstairs, my NF7-S decided to
    give nonsense voltages again. Although this was very frustrating, I'm more
    than happy that it works at all!
     
    SpellmanXP, Oct 11, 2004
    #1
    1. Advertisements

  2. SpellmanXP

    Ed Light Guest

    As to nonsense voltages, you could get a bunch of the little red insulating
    washers at a computer shop and put them on both sides of the motherboard at
    each mounting point. Just in case it's shorting to ground.


    --
    Ed Light

    Smiley :-/
    MS Smiley :-\

    Send spam to the FTC at

    Thanks, robots.
     
    Ed Light, Oct 11, 2004
    #2
    1. Advertisements

  3. Make sure the little bit of anti-static plastic doesn't melt! I dont know
    what temp this would happen, but its only thin plastic!
     
    Gareth Tuckwell, Oct 11, 2004
    #3
  4. SpellmanXP

    SpellmanXP Guest

    I wondered about this too!

    I'm sure it won't be long before I make another attempt to fix the sensor,
    so I'll probably replace it with "something better" - but what???
     
    SpellmanXP, Oct 11, 2004
    #4
  5. Make sure the little bit of anti-static plastic doesn't melt! I dont know
    What about a bit of electrical insulating tape or even celotape? I don't
    suppose either would melt, but I know nothing about their properties
    regarding heat - anyone help out here - is celotape conductive? What temp
    melts it?
     
    Gareth Tuckwell, Oct 11, 2004
    #5
  6. SpellmanXP

    Rusty Guest

    Electrical tape is not conductive but celotape can be conductive and it
    melts.
    Try some thermal tape or strips like you get with a heat sink. It's not
    suppose to conduct electricity.
    You might check the motherboard connection where the thermal resistor
    attaches, could be loose.
    Sounds like a bad sensor (thermal resistor), is the MB still under warranty?
    Don't forget to disable the thermal safety features in the BIOS they will
    shut down the computer with a two tone siren if the temperature exceeds the
    thresholds.
     
    Rusty, Oct 11, 2004
    #6
  7. SpellmanXP

    Ed Light Guest

    maybe the liquid insulation stuff?


    --
    Ed Light

    Smiley :-/
    MS Smiley :-\

    Send spam to the FTC at

    Thanks, robots.
     
    Ed Light, Oct 12, 2004
    #7
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.