High pitch noise coming from old motherboard

Discussion in 'Computer Hardware, Devices and Accessories' started by MarcusD, Jan 10, 2016.

  1. MarcusD
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    MarcusD baby Near

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    I has to swap PCs with grandma, and now I got her old crap she had.

    Now, when the mobo is powered, it gives out a somewhat low-pitched noise (coming from around the ethernet port). If I plug in the ethernet cable, the noise gets high-pitched, and it just kills my ears.

    It's a very, very old VIA (probably ASUS) motherboard.

    Edit: also, the integrated graphics regarding to grandma's ├╝ber-super CRT monitor, if it's idle, the refreshrate goes to a few *kilohertz*!
     
    Last edited by MarcusD, Jan 10, 2016
  2. The Real Jdbye

    The Real Jdbye Always Remember 30/07/08

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    Alola
    Probably the fans.
     
  3. MarcusD
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    MarcusD baby Near

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    I'm on mobile, and I accidently clicked post :P I edited it now.
     
  4. The Real Jdbye

    The Real Jdbye Always Remember 30/07/08

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    Okay, it sounds more like a noisy voltage converter now. Those can sometimes make very high-pitched whining (especially if they are cheap), I don't think there's much you can do about it. It could be something else but that's the first thing that comes to mind.
     
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  5. MarcusD
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    MarcusD baby Near

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    Yes, that may be the issue. I don't know if it's the case, because I'm afraid to turn the computer on while the case is not on, because the case is shocks me if I touch it. It really hurts.
     
  6. The Real Jdbye

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    It shouldn't shock you, that sounds like there is AC current leaking into ground. If you can, use a grounded socket which should prevent that from happening.
    I actually have a similar issue with my desktop, but I think it's the surge protector that's causing it due to not being properly grounded, since there are hardly any grounded sockets in my apartment. If I touch the end of a plugged in USB cable it shocks me, at first I thought "Damn, that's really sharp", but having looked it up it appears to be caused by AC current leaking into ground and is solved by simply using a grounded socket. The case itself doesn't shock me though, it's only when I touch the end of a plugged in USB cable.
     
  7. MarcusD
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    MarcusD baby Near

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    We don't have any 3-pin power outlets either (the one with the extra ground-pin). Here only the case is shocking me, everything else is fine touching.

    I managed to turn on the computer without the side cover, and I noticed that the noise is coming from around the PCNet HT2001 0234 chip. The weirdest thing is that the noise works similar to unshielded power adaptors. If you have it under current, it gives out a low noise. If you plug it in into a device, it makes a medium noise, and after it detected that there's really a device that's gonna be charged, it gives out a very loud and high-pitched noise.

    Also, if I "decharge" the case, it no longer shocks me, even after a long time. It only shocks me if I turn it on after a long power-off time.

    Also, I absolutely can't identify the motherboard. This is a Spacewalker MV42 v1.3 motherboard, that it has a VIA PLE133 chipset with VIA VT8233 south bridge controller, a PCNet HT2001 0234 ethernet-chip-thingy, and this one has an Intel Celeron in it. Also, it has an AmiBIOS BIOS ROM chip.
     
  8. pwsincd

    pwsincd Garage Flower

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    omg no cpc wtf ?
     
  9. MarcusD
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    MarcusD baby Near

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    Could you please say that in normal English? I don't know what "cpc" is.
     
    Last edited by MarcusD, Jan 10, 2016 - Reason: fixed typo
  10. pwsincd

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    cpc : circuit protective conductor ... or ground or earth..
     
  11. MarcusD
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    MarcusD baby Near

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    Ohh. Ye, I don't think this monster has any protection in it.

    Btw, it looks like if the PC is turned on, the noise gets much quieter than in powered-off mode. Maybe the PCNet chip gets too much voltage when the PC is powered off. I'm afraid to put my GTS 450 in this old monster :P