Motherboard issue?

Discussion in 'Computer Information' started by Justin Shifflett, Jul 12, 2010.

  1. I was told I should post here.

    I don't want to have to replace the motherboard if I don't have to.
    But I think I do.

    My PC will turn on. The fans will run. But the PC won't detect the
    keyboard. It will however detect the mouse (it's optical, and glows
    red). Nothing will happen on the monitor, and the monitor light will
    turn yellow like nothing is on-- but the monitor works fine, as it's
    being used on the current PC I'm on.

    I called HP (The company that made my computer). They went through
    the steps with me-- getting Static Electricity out of the system,
    reseating the Ram, listening for beeps (there weren't any as far as I
    could tell.) ANd they said they thought it was a Motherboard issue.

    I don't know what else to do. I've tried just about everything I can
    think of. It's weird how the mouse will be read, but nothing else
    will. I dont' know if it's the motherboard, the CPU, or what.

    Any tips?
    Justin Shifflett, Jul 12, 2010
    #1
    1. Advertising

  2. Justin Shifflett

    Paul Guest

    Justin Shifflett wrote:
    > I was told I should post here.
    >
    > I don't want to have to replace the motherboard if I don't have to.
    > But I think I do.
    >
    > My PC will turn on. The fans will run. But the PC won't detect the
    > keyboard. It will however detect the mouse (it's optical, and glows
    > red). Nothing will happen on the monitor, and the monitor light will
    > turn yellow like nothing is on-- but the monitor works fine, as it's
    > being used on the current PC I'm on.
    >
    > I called HP (The company that made my computer). They went through
    > the steps with me-- getting Static Electricity out of the system,
    > reseating the Ram, listening for beeps (there weren't any as far as I
    > could tell.) ANd they said they thought it was a Motherboard issue.
    >
    > I don't know what else to do. I've tried just about everything I can
    > think of. It's weird how the mouse will be read, but nothing else
    > will. I dont' know if it's the motherboard, the CPU, or what.
    >
    > Any tips?


    I like to start with the model number. Like "Pavilion 1234" or the like.

    Using the model number, I like to check to see whether that computer
    has any "favorite" failure modes. Knowing the approximate age also
    helps, as a particular power supply failure, ruins the motherboard and
    things like the hard drive.

    One test is to:

    1) Remove all AC power to the computer. Unplug it to be safe.
    2) Remove the RAM sticks and place them in an antistatic bag for
    safe keeping.
    3) Turn on the computer and listen for beeps.
    4) If you hear beeps, it means the CPU is working. The CPU is what
    helped make the beeps.
    5) If turning off all power, adding one stick of RAM back, and powering
    up yields no beep, after step (3) gave beeps, it could be a bad stick of
    RAM. If the RAM is bad in low memory locations below 640K, sometimes
    that causes the BIOS to die before there are beeps. (That has happened
    to me on an Nforce2 motherboard.)

    A bad CMOS battery has been known to prevent a PC from POSTing. Usually
    you'll find a CR2032 coin cell on the motherboard, and it should be delivering
    3.0 volts or a bit more. If it is much below 2.3 volts, that might cause
    problems. Sometimes, it drops all the way to zero, and some motherboards
    don't seem to be able to start when that happens. I don't really know the
    reason why that happens, because as far as I know, all the important
    circuitry should be getting power from the power supply.

    You should also do a visual inspection for bad capacitors. In the pictures
    here, you can see the area around the pressure relief seams is starting
    to bulge, which means pressure is building up inside. The rubber seal on the
    bottom of the electrolytic capacitor can also push out of the metal can, causing
    the cap to tilt to one side. When a cap bursts, orange-brown liquid will dry
    near the seams or spill onto the motherboard surface. For things like caps in
    the Vcore circuit, that will eventually lead to a failure to POST, or instability
    and crashing while in Windows.

    http://www.badcaps.net/images/caps/kt7/image004.png

    I've even had those bad capacitors, inside my Antec power supply. That
    caused the supply to "sizzle" at startup, and eventually resulted in the
    processor crashing in the BIOS.

    Paul
    Paul, Jul 12, 2010
    #2
    1. Advertising

  3. On 11 July, 22:44, Paul <> wrote:
    > Justin Shifflett wrote:
    > > I was told I should post here.

    >
    > > I don't want to have to replace the motherboard if I don't have to.
    > > But I think I do.

    >
    > > My PC will turn on. The fans will run. But the PC won't detect the
    > > keyboard. It will however detect the mouse (it's optical, and glows
    > > red). Nothing will happen on the monitor, and the monitor light will
    > > turn yellow like nothing is on-- but the monitor works fine, as it's
    > > being used on the current PC I'm on.

    >
    > > I called HP (The company that made my computer). They went through
    > > the steps with me-- getting Static Electricity out of the system,
    > > reseating the Ram, listening for beeps (there weren't any as far as I
    > > could tell.) ANd they said they thought it was a Motherboard issue.

    >
    > > I don't know what else to do. I've tried just about everything I can
    > > think of. It's weird how the mouse will be read, but nothing else
    > > will. I dont' know if it's the motherboard, the CPU, or what.

    >
    > > Any tips?

    >
    > I like to start with the model number. Like "Pavilion 1234" or the like.
    >
    > Using the model number, I like to check to see whether that computer
    > has any "favorite" failure modes. Knowing the approximate age also
    > helps, as a particular power supply failure, ruins the motherboard and
    > things like the hard drive.
    >
    > One test is to:
    >
    > 1) Remove all AC power to the computer. Unplug it to be safe.
    > 2) Remove the RAM sticks and place them in an antistatic bag for
    > safe keeping.
    > 3) Turn on the computer and listen for beeps.
    > 4) If you hear beeps, it means the CPU is working. The CPU is what
    > helped make the beeps.
    > 5) If turning off all power, adding one stick of RAM back, and powering
    > up yields no beep, after step (3) gave beeps, it could be a bad stick of
    > RAM. If the RAM is bad in low memory locations below 640K, sometimes
    > that causes the BIOS to die before there are beeps. (That has happened
    > to me on an Nforce2 motherboard.)
    >
    > A bad CMOS battery has been known to prevent a PC from POSTing. Usually
    > you'll find a CR2032 coin cell on the motherboard, and it should be delivering
    > 3.0 volts or a bit more. If it is much below 2.3 volts, that might cause
    > problems. Sometimes, it drops all the way to zero, and some motherboards
    > don't seem to be able to start when that happens. I don't really know the
    > reason why that happens, because as far as I know, all the important
    > circuitry should be getting power from the power supply.
    >
    > You should also do a visual inspection for bad capacitors. In the pictures
    > here, you can see the area around the pressure relief seams is starting
    > to bulge, which means pressure is building up inside. The rubber seal on the
    > bottom of the electrolytic capacitor can also push out of the metal can, causing
    > the cap to tilt to one side. When a cap bursts, orange-brown liquid will dry
    > near the seams or spill onto the motherboard surface. For things like caps in
    > the Vcore circuit, that will eventually lead to a failure to POST, or instability
    > and crashing while in Windows.
    >
    > http://www.badcaps.net/images/caps/kt7/image004.png
    >
    > I've even had those bad capacitors, inside my Antec power supply. That
    > caused the supply to "sizzle" at startup, and eventually resulted in the
    > processor crashing in the BIOS.
    >
    > Paul


    The model is HP Pavilion a600f It's almost 2 years old (Got in August
    of 08)

    With all ram removed, the computer makes absolutely no beeps.

    I've been having BSOD's recently, mostly on Cold Boot. Then things
    would be fine.

    My motherboard, if it matters, is a Foxconn MCP73M02H1

    The capacitors look fine.

    I really appreciate the help, and you really seem to know your stuff.
    Justin Shifflett, Jul 12, 2010
    #3
  4. Justin Shifflett

    Paul Guest

    Justin Shifflett wrote:
    > On 11 July, 22:44, Paul <> wrote:
    >> Justin Shifflett wrote:
    >>> I was told I should post here.
    >>> I don't want to have to replace the motherboard if I don't have to.
    >>> But I think I do.
    >>> My PC will turn on. The fans will run. But the PC won't detect the
    >>> keyboard. It will however detect the mouse (it's optical, and glows
    >>> red). Nothing will happen on the monitor, and the monitor light will
    >>> turn yellow like nothing is on-- but the monitor works fine, as it's
    >>> being used on the current PC I'm on.
    >>> I called HP (The company that made my computer). They went through
    >>> the steps with me-- getting Static Electricity out of the system,
    >>> reseating the Ram, listening for beeps (there weren't any as far as I
    >>> could tell.) ANd they said they thought it was a Motherboard issue.
    >>> I don't know what else to do. I've tried just about everything I can
    >>> think of. It's weird how the mouse will be read, but nothing else
    >>> will. I dont' know if it's the motherboard, the CPU, or what.
    >>> Any tips?

    >> I like to start with the model number. Like "Pavilion 1234" or the like.
    >>
    >> Using the model number, I like to check to see whether that computer
    >> has any "favorite" failure modes. Knowing the approximate age also
    >> helps, as a particular power supply failure, ruins the motherboard and
    >> things like the hard drive.
    >>
    >> One test is to:
    >>
    >> 1) Remove all AC power to the computer. Unplug it to be safe.
    >> 2) Remove the RAM sticks and place them in an antistatic bag for
    >> safe keeping.
    >> 3) Turn on the computer and listen for beeps.
    >> 4) If you hear beeps, it means the CPU is working. The CPU is what
    >> helped make the beeps.
    >> 5) If turning off all power, adding one stick of RAM back, and powering
    >> up yields no beep, after step (3) gave beeps, it could be a bad stick of
    >> RAM. If the RAM is bad in low memory locations below 640K, sometimes
    >> that causes the BIOS to die before there are beeps. (That has happened
    >> to me on an Nforce2 motherboard.)
    >>
    >> A bad CMOS battery has been known to prevent a PC from POSTing. Usually
    >> you'll find a CR2032 coin cell on the motherboard, and it should be delivering
    >> 3.0 volts or a bit more. If it is much below 2.3 volts, that might cause
    >> problems. Sometimes, it drops all the way to zero, and some motherboards
    >> don't seem to be able to start when that happens. I don't really know the
    >> reason why that happens, because as far as I know, all the important
    >> circuitry should be getting power from the power supply.
    >>
    >> You should also do a visual inspection for bad capacitors. In the pictures
    >> here, you can see the area around the pressure relief seams is starting
    >> to bulge, which means pressure is building up inside. The rubber seal on the
    >> bottom of the electrolytic capacitor can also push out of the metal can, causing
    >> the cap to tilt to one side. When a cap bursts, orange-brown liquid will dry
    >> near the seams or spill onto the motherboard surface. For things like caps in
    >> the Vcore circuit, that will eventually lead to a failure to POST, or instability
    >> and crashing while in Windows.
    >>
    >> http://www.badcaps.net/images/caps/kt7/image004.png
    >>
    >> I've even had those bad capacitors, inside my Antec power supply. That
    >> caused the supply to "sizzle" at startup, and eventually resulted in the
    >> processor crashing in the BIOS.
    >>
    >> Paul

    >
    > The model is HP Pavilion a600f It's almost 2 years old (Got in August
    > of 08)
    >
    > With all ram removed, the computer makes absolutely no beeps.
    >
    > I've been having BSOD's recently, mostly on Cold Boot. Then things
    > would be fine.
    >
    > My motherboard, if it matters, is a Foxconn MCP73M02H1
    >
    > The capacitors look fine.
    >
    > I really appreciate the help, and you really seem to know your stuff.


    Do you have any warranty left on the thing ? You don't want
    to pay for stuff you don't have to, if there is warranty
    left on it.

    Based on your "having BSOD's recently, mostly on Cold Boot, then things
    would be fine", I'd say this is a power supply issue. It sounds almost
    exactly like my Antec power supply symptoms. I'd probably
    start by checking supply voltages with a multimeter, and verify the
    Power_Good signal on the main connector, was being asserted after
    you start the thing. The power supply sends the logic signal Power_Good,
    after all the voltages have stabilized out of the power supply. The
    motherboard comes out of reset, once Power_Good is there, and
    any "local Power_Good" from the motherboard itself, is true.
    The motherboard has its own onboard regulators, and some of those
    have a status signal indicating they're ready. When all power
    regulating devices are happy, that is when the BIOS POST starts.

    You can find copies of the ATX spec, if you're curious about how it works,
    or what color wire does what function.

    http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf

    Depending on what is appearing in the BSOD, that may help refine
    the problem. If BSODs crash in random pieces of code every time,
    then you'd assume it is some outside force like the power supply
    failing. If the same routine is named every time, like something
    beginning in "nv", it could be a graphics driver running into
    problems with a failing GPU inside your Northbridge (under the
    heatsink). The predecessor to the 7100, the 6100/6150, had
    a few problems with poorly tested built-in GPUs. Some people
    saw colored blocks from their built-in graphics.

    http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01357119&lc=en&cc=us&dlc=en&product=3644689

    If you don't have a multimeter, and aren't interested in probing
    stuff like that, you can start by swapping the power supply. Or
    have a local shop do the debug for you, and identify to the nearest
    failed component, what is busted ("motherboard" or "power supply").
    Processors hardly ever fail, your RAM test didn't conclusively
    indicate a problem, so at the moment, I'd have to assume motherboard
    or PSU as a starting point. And PSU is the easiest one to swap first.
    (You can even use a 20 pin supply in the 24 pin connector, as the
    extra four pins are redundant and other wires already carry that
    power.)

    (20 pin goes up against one end of the 24 pin connector, latch side to latch side)
    http://www.playtool.com/pages/psuconnectors/20in24.jpg

    If I'm mistaken, and you've actually had a video card stuffed in
    the video card slot, you could also pull that out, and try running
    the computer from the built-in video. My suggestions above are
    based on assuming you're using the 7100 built-in graphics (rear
    video connectors in the I/O plate area). Some Nvidia chipset
    motherboards in the past, have had excessively sensitive PCI Express
    slots, such that a slot would blow out without much provocation.

    This is a really silly idea, but every once in a while, a poster
    has a problem like this, and the problem turns out to be a loose
    power cord. They work loose, where they plug into the supply on the
    back of the computer. That sometimes simulates a "weak supply" syndrome.
    Pretty low odds, but I have to mention it.

    In addition to the BSODs, sometimes the supply will give additional
    hints -

    1) A puff of smoke at startup - almost looks like dust.
    Perhaps you can also smell something a bit different than normal.

    2) Weird noises. Sizzling. Coil noise. Whining. Anything that
    might indicate a component under stress.

    3) When computers have fixed speed fans, after a while, you get used
    to the "stability level" of the fans. The human ear is sensitive
    to pitch. On two power supplies here, just before they failed,
    the fan speed on the fixed fans started to "wander" a bit. That's
    another thing I look for, is a change in the stable tone of fixed
    speed fans. If your fans are speed controlled, and constantly
    varying, then you can't use this criterion. HPs and Dells are likely
    to have variable speed cooling fans, so this test probably won't
    help you.

    HTH,
    Paul
    Paul, Jul 12, 2010
    #4
  5. On 11 July, 23:21, Paul <> wrote:
    > Justin Shifflett wrote:
    > > On 11 July, 22:44, Paul <> wrote:
    > >> Justin Shifflett wrote:
    > >>> I was told I should post here.
    > >>> I don't want to have to replace the motherboard if I don't have to.
    > >>> But I think I do.
    > >>> My PC will turn on. The fans will run. But the PC won't detect the
    > >>> keyboard. It will however detect the mouse (it's optical, and glows
    > >>> red). Nothing will happen on the monitor, and the monitor light will
    > >>> turn yellow like nothing is on-- but the monitor works fine, as it's
    > >>> being used on the current PC I'm on.
    > >>> I called HP (The company that made my computer). They went through
    > >>> the steps with me-- getting Static Electricity out of the system,
    > >>> reseating the Ram, listening for beeps (there weren't any as far as I
    > >>> could tell.) ANd they said they thought it was a Motherboard issue.
    > >>> I don't know what else to do. I've tried just about everything I can
    > >>> think of. It's weird how the mouse will be read, but nothing else
    > >>> will. I dont' know if it's the motherboard, the CPU, or what.
    > >>> Any tips?
    > >> I like to start with the model number. Like "Pavilion 1234" or the like.

    >
    > >> Using the model number, I like to check to see whether that computer
    > >> has any "favorite" failure modes. Knowing the approximate age also
    > >> helps, as a particular power supply failure, ruins the motherboard and
    > >> things like the hard drive.

    >
    > >> One test is to:

    >
    > >> 1) Remove all AC power to the computer. Unplug it to be safe.
    > >> 2) Remove the RAM sticks and place them in an antistatic bag for
    > >> safe keeping.
    > >> 3) Turn on the computer and listen for beeps.
    > >> 4) If you hear beeps, it means the CPU is working. The CPU is what
    > >> helped make the beeps.
    > >> 5) If turning off all power, adding one stick of RAM back, and powering
    > >> up yields no beep, after step (3) gave beeps, it could be a bad stick of
    > >> RAM. If the RAM is bad in low memory locations below 640K, sometimes
    > >> that causes the BIOS to die before there are beeps. (That has happened
    > >> to me on an Nforce2 motherboard.)

    >
    > >> A bad CMOS battery has been known to prevent a PC from POSTing. Usually
    > >> you'll find a CR2032 coin cell on the motherboard, and it should be delivering
    > >> 3.0 volts or a bit more. If it is much below 2.3 volts, that might cause
    > >> problems. Sometimes, it drops all the way to zero, and some motherboards
    > >> don't seem to be able to start when that happens. I don't really know the
    > >> reason why that happens, because as far as I know, all the important
    > >> circuitry should be getting power from the power supply.

    >
    > >> You should also do a visual inspection for bad capacitors. In the pictures
    > >> here, you can see the area around the pressure relief seams is starting
    > >> to bulge, which means pressure is building up inside. The rubber seal on the
    > >> bottom of the electrolytic capacitor can also push out of the metal can, causing
    > >> the cap to tilt to one side. When a cap bursts, orange-brown liquid will dry
    > >> near the seams or spill onto the motherboard surface. For things like caps in
    > >> the Vcore circuit, that will eventually lead to a failure to POST, or instability
    > >> and crashing while in Windows.

    >
    > >>http://www.badcaps.net/images/caps/kt7/image004.png

    >
    > >> I've even had those bad capacitors, inside my Antec power supply. That
    > >> caused the supply to "sizzle" at startup, and eventually resulted in the
    > >> processor crashing in the BIOS.

    >
    > >> Paul

    >
    > > The model is HP Pavilion a600f It's almost 2 years old (Got in August
    > > of 08)

    >
    > > With all ram removed, the computer makes absolutely no beeps.

    >
    > > I've been having BSOD's recently, mostly on Cold Boot. Then things
    > > would be fine.

    >
    > > My motherboard, if it matters, is a Foxconn MCP73M02H1

    >
    > > The capacitors look fine.

    >
    > > I really appreciate the help, and you really seem to know your stuff.

    >
    > Do you have any warranty left on the thing ? You don't want
    > to pay for stuff you don't have to, if there is warranty
    > left on it.
    >
    > Based on your "having BSOD's recently, mostly on Cold Boot, then things
    > would be fine", I'd say this is a power supply issue. It sounds almost
    > exactly like my Antec power supply symptoms. I'd probably
    > start by checking supply voltages with a multimeter, and verify the
    > Power_Good signal on the main connector, was being asserted after
    > you start the thing. The power supply sends the logic signal Power_Good,
    > after all the voltages have stabilized out of the power supply. The
    > motherboard comes out of reset, once Power_Good is there, and
    > any "local Power_Good" from the motherboard itself, is true.
    > The motherboard has its own onboard regulators, and some of those
    > have a status signal indicating they're ready. When all power
    > regulating devices are happy, that is when the BIOS POST starts.
    >
    > You can find copies of the ATX spec, if you're curious about how it works,
    > or what color wire does what function.
    >
    > http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2...
    >
    > Depending on what is appearing in the BSOD, that may help refine
    > the problem. If BSODs crash in random pieces of code every time,
    > then you'd assume it is some outside force like the power supply
    > failing. If the same routine is named every time, like something
    > beginning in "nv", it could be a graphics driver running into
    > problems with a failing GPU inside your Northbridge (under the
    > heatsink). The predecessor to the 7100, the 6100/6150, had
    > a few problems with poorly tested built-in GPUs. Some people
    > saw colored blocks from their built-in graphics.
    >
    > http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01357119&lc=en&c...
    >
    > If you don't have a multimeter, and aren't interested in probing
    > stuff like that, you can start by swapping the power supply. Or
    > have a local shop do the debug for you, and identify to the nearest
    > failed component, what is busted ("motherboard" or "power supply").
    > Processors hardly ever fail, your RAM test didn't conclusively
    > indicate a problem, so at the moment, I'd have to assume motherboard
    > or PSU as a starting point. And PSU is the easiest one to swap first.
    > (You can even use a 20 pin supply in the 24 pin connector, as the
    > extra four pins are redundant and other wires already carry that
    > power.)
    >
    > (20 pin goes up against one end of the 24 pin connector, latch side to latch side)http://www.playtool.com/pages/psuconnectors/20in24.jpg
    >
    > If I'm mistaken, and you've actually had a video card stuffed in
    > the video card slot, you could also pull that out, and try running
    > the computer from the built-in video. My suggestions above are
    > based on assuming you're using the 7100 built-in graphics (rear
    > video connectors in the I/O plate area). Some Nvidia chipset
    > motherboards in the past, have had excessively sensitive PCI Express
    > slots, such that a slot would blow out without much provocation.
    >
    > This is a really silly idea, but every once in a while, a poster
    > has a problem like this, and the problem turns out to be a loose
    > power cord. They work loose, where they plug into the supply on the
    > back of the computer. That sometimes simulates a "weak supply" syndrome.
    > Pretty low odds, but I have to mention it.
    >
    > In addition to the BSODs, sometimes the supply will give additional
    > hints -
    >
    > 1) A puff of smoke at startup - almost looks like dust.
    > Perhaps you can also smell something a bit different than normal.
    >
    > 2) Weird noises. Sizzling. Coil noise. Whining. Anything that
    > might indicate a component under stress.
    >
    > 3) When computers have fixed speed fans, after a while, you get used
    > to the "stability level" of the fans. The human ear is sensitive
    > to pitch. On two power supplies here, just before they failed,
    > the fan speed on the fixed fans started to "wander" a bit. That's
    > another thing I look for, is a change in the stable tone of fixed
    > speed fans. If your fans are speed controlled, and constantly
    > varying, then you can't use this criterion. HPs and Dells are likely
    > to have variable speed cooling fans, so this test probably won't
    > help you.
    >
    > HTH,
    > Paul


    The fans come on, the power light comes on. And the mouse is read.
    Shouldn't that mean that it's not a PSU Issue? I went through a flow
    chart, and it moved me to motherboard issue or CPU issue.

    My bsod's cited:
    svchost.exe
    WerFault.exe
    services.exe
    ntkrnlmp.exe ( nt! ?? ::FNODOBFM::`string'+1829 )

    The last one cited Firefox.
    Justin Shifflett, Jul 12, 2010
    #5
  6. Adding that the light on the PSU unit is solid green. Stays green a
    little while after unhooking the power.

    It's a Bestec ATX-250-12z
    Justin Shifflett, Jul 12, 2010
    #6
  7. Justin Shifflett

    Paul Guest

    Justin Shifflett wrote:
    > Adding that the light on the PSU unit is solid green. Stays green a
    > little while after unhooking the power.
    >
    > It's a Bestec ATX-250-12z
    >


    Uh oh!

    The history is, the Bestec ATX-250, was the brand of supply that
    would fail "overvoltage" and blow other components like the motherboard
    and hard drive. The bad supplies might have been ATX250-12e , while
    your one has "z" on the end and might be a different design.

    Would Bestec have learned their lesson, and designed a better power
    supply ? I can't answer that. I don't know enough about the company.
    With the grief they've caused, I wonder why any manufacturer would
    continue to do business with them. Your computer is relatively new,
    compared to the Emachines and other computers that 12e supply damaged.

    One test you can try, is slave the hard drive from the non-functional
    computer, to another computer, and see whether the hard drive can be
    read or not. (Testing the hard drive, is to see if the power supply
    has ruined stuff on you. If the hard drive is good, then that
    increases the odds you can repair the machine at moderate cost.)

    The hard drive has two transient suppressors, on the +5V and +12V
    rails. They're not designed to protect against power supply failures.
    They are present to protect the hard drive against overshoot when
    the power goes off. At least one poster figured this all out, and
    provided me with an education. He found burned components on his
    hard drive, traced down the numbers, and then I read up on them.
    If you had a sustained overvoltage event, and the hard drive
    no longer responded, the burned state of those one or two
    components, near where the power comes into the drive on the
    drive controller board, would provide some confirmation there
    was an overvoltage failure. A high current flows through the
    transient suppressor, if the ATX 12V drive voltage goes to 15V.
    Because the high voltage is not a transient, but a steady
    condition, it gives the components time to burn up.

    You could use a multimeter and verify the power supply voltages.
    At this point, it probably doesn't make any difference any more,
    as to how many more times you turn on the power supply. If it
    has damaged the computer, it probably can't do any additional damage.

    Modern power supplies have features such as

    1) Overvoltage protection. Supply shuts off, if, for example, the
    3.3V rail rises to 4.7V. That can also help in situations, where
    one rail of the supply, gets shorted to another rail.

    2) Overcurrent protection. Sometimes used on multiple output 12V supplies,
    limiting current flow on each so-called "separate" rail. I suppose
    that leads to a shutdown as well.

    3) Overtemperature protection. The power supply may have a thermistor
    on one of the internal heatsinks, to detect an effective cooling
    failure, or cover the case where the power supply is delivering
    too much total power for its own good.

    You can save a few pennies on a power supply design, by removing that
    stuff. Then, on a failure, there is a lot more collateral damage.

    At this point, you can change the supply, but the symptoms might not
    change, due to the damage it did to the motherboard. In terms of
    "swap order", I'd still do the power supply first. Since the original
    is a 250W, you should be able to use just about any ATX compatible
    supply you have near you, for a quick test. But if the motherboard
    and/or hard drive got damaged, the symptoms might not change
    with the new supply.

    And I don't see any of those motherboards on Ebay. The main reason
    for wanting the same motherboard, is so the royalty OEM OS install,
    will continue to restore OK to the machine. You can also reinstall
    from a regular Windows CD, but the CD type has to match the original
    install, so that the license key on the machine will work.

    I sure hope there is some warranty time left on the computer. If it was
    only a one year warranty, chances are you're screwed. Talk to HP
    anyway, and see what they say.

    The mouse light may be coming on, because it is running from +5VSB
    from the power supply. Perhaps that rail is OK, as +5VSB comes from
    a separate part of the supply.

    Knowing it's a Bestec, doesn't change the repair procedure that
    much, except to suggest one additional test, to check for
    collateral damage. The hard drive and optical drive could be
    ruined, if +5V or +12V go higher than normal.

    Paul
    Paul, Jul 12, 2010
    #7
  8. I went ahead and tested another PSU. The fans started, but nothing
    else. So I'm guessing it's likely the motherboard now. Hopefully
    replacing it with an identical one will prevent data loss.
    Justin Shifflett, Jul 13, 2010
    #8
  9. Justin Shifflett

    Paul Guest

    Justin Shifflett wrote:
    > I went ahead and tested another PSU. The fans started, but nothing
    > else. So I'm guessing it's likely the motherboard now. Hopefully
    > replacing it with an identical one will prevent data loss.
    >


    I'm curious about the hard drive. Test it on another computer
    and see if it survived.

    Paul
    Paul, Jul 13, 2010
    #9
  10. I can't tell what the trouble is, but one thing that should be on your list
    is a failed Power Supply.

    You didn't say, but the keyboard could be a PS2 and the Mouse could be a
    USB, and this could explain why there is power to the light on the mouse,
    but no response from the keyboard. Of course,l the keyboard could be USB and
    the mouse PS2, and the same symptoms could occur.

    I don't know what other loads are driven by the voltage that goes to the the
    different circuits, But the USB is usually about 5v, so anything that runs
    from 5v would not work, which is lots of stuff.

    You can buy a power supply for under 50 dollars and get greater capacity
    than you have now.

    You could test the power supply with a volt meter, or maybe by unplugging
    all but the essential loads. If your machine worked until you added the most
    recent accessory, then it's possible that the new accessory overloaded the
    power supply. Sometimes you can unplug the overload and get the power supply
    back. If this is the case with your problem, then a new power supply with
    more power capability is in your future.





    "Justin Shifflett" <> wrote in message
    news:...
    >I was told I should post here.
    >
    > I don't want to have to replace the motherboard if I don't have to.
    > But I think I do.
    >
    > My PC will turn on. The fans will run. But the PC won't detect the
    > keyboard. It will however detect the mouse (it's optical, and glows
    > red). Nothing will happen on the monitor, and the monitor light will
    > turn yellow like nothing is on-- but the monitor works fine, as it's
    > being used on the current PC I'm on.
    >
    > I called HP (The company that made my computer). They went through
    > the steps with me-- getting Static Electricity out of the system,
    > reseating the Ram, listening for beeps (there weren't any as far as I
    > could tell.) ANd they said they thought it was a Motherboard issue.
    >
    > I don't know what else to do. I've tried just about everything I can
    > think of. It's weird how the mouse will be read, but nothing else
    > will. I dont' know if it's the motherboard, the CPU, or what.
    >
    > Any tips?
    Jeff Strickland, Jul 13, 2010
    #10
  11. "Justin Shifflett" <> wrote in message
    news:...
    >I went ahead and tested another PSU. The fans started, but nothing
    > else. So I'm guessing it's likely the motherboard now. Hopefully
    > replacing it with an identical one will prevent data loss.
    >



    Data loss is not related to the motherboard. If you're convinced that you
    need a motherboard, then now is a great time to consider an upgrade. Any
    data that is lost or retained is in the HDD, so you can makek changes to the
    motherboard and not affect the data loss/retention part of the problem.

    Your test of the PSU is inconclusive at best. If you have a bad PSU that is
    not able to feed ALL OF THE VOLTAGES, but it does feed SOME of them, then
    you might have fans that can come on but not have other critical things take
    place. A valid test is to name your machine A, and get another machine named
    B. If your mother board fails in both A and B, then your motherboard is at
    fault. If the motherboard from B works until you put it into A, and your
    motherboard works in B but not A, then the Power Supply in A is highly
    suspect.

    Nevermind, you swapped the PSU from B to A, and got no improvement in the
    symptom set. This should be a good test, assuming B was working when you
    took the power supply out of it, and worked again when you put it back. If
    you put the supply from A into B, and B works, then this further supports
    the integrity of the power supply, and points to the motherboard as the
    fault source.

    You also have one more item, the Boot Sector of the HDD. (There was
    discussion of the RAM, and I don't recall what conclusion you drew from the
    tests described there.)

    You would isolate this by taking the HDD from B and installing it into A to
    see if A will come up properly.
    Jeff Strickland, Jul 13, 2010
    #11
  12. Update: I've got the keyboard registering now. But not much else
    changing. Ethernet is still not detected. Awaiting the new
    motherboard to come in...
    Justin Shifflett, Jul 15, 2010
    #12
    1. Advertising

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

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Primster

    Motherboard Issue

    Primster, Jul 1, 2003, in forum: Computer Support
    Replies:
    4
    Views:
    1,027
    Mike Stevenson
    Jul 8, 2003
  2. John

    Motherboard / Power SUpply Issue

    John, Jul 24, 2003, in forum: Computer Support
    Replies:
    4
    Views:
    3,300
    Jeffrey Edwards
    Jul 24, 2003
  3. Lee Davison

    Motherboard - Video Card Issue

    Lee Davison, Oct 5, 2005, in forum: Computer Support
    Replies:
    1
    Views:
    474
    Martik
    Oct 5, 2005
  4. DeMoN LaG

    Motherboard issue

    DeMoN LaG, Feb 11, 2004, in forum: Computer Information
    Replies:
    7
    Views:
    566
    DeMoN LaG
    Feb 12, 2004
  5. sub
    Replies:
    9
    Views:
    2,615
    SteveM
    Jun 26, 2006
Loading...

Share This Page