Computer Hardware Gurus...

Discussion in 'Fred's House of Pancakes' started by Patrick Wong, Apr 7, 2010.

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  1. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Connect the speaker so you can hear any beep codes, if any.

    Did the CPU fan spin when you power it up?
     
    #21 usbseawolf2000, Apr 8, 2010
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I connected the speaker and turned the motherboard on. No sound.

    I don't have the fan connected or installed because the CPU chip is out. However the fan was working when the entire laptop had been previously assembled.
     
    #22 Patrick Wong, Apr 8, 2010
  3. usbseawolf2000

    usbseawolf2000 HSD PhD

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    What do you mean you connected an external power supply? You have another laptop PSU?

    It sounds like the BIOS is not booting. Once the BIOS starts, it checks for CPU, RAM, etc... Can you measure the voltage from the CPU fan pins?
     
    #23 usbseawolf2000, Apr 8, 2010
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I am talking about the rectangular black plastic power supply external to the laptop: 120 VAC to 18.5VDC @ 3.5A provided to the laptop. That plugs into the side of the laptop. An LED turns on whenever the power supply is plugged in.

    The power input socket appears to contain a tiny power supply, as the back end of it has a 6-wire cable leading to the motherboard.

    I could measure the fan socket voltage; but the fan was spinning before, when the computer was put together. What voltage am I looking for?
     
    #24 Patrick Wong, Apr 8, 2010
  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I am assuming it should be 12v nominal like desktop. Look for fluctuation in voltage also... just to make sure the PSU is regulating constant voltage.
     
    #25 usbseawolf2000, Apr 8, 2010
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Should I disconnect the power cable where it plugs into the motherboard, and measure the voltages at the cable connector?
     
    #26 Patrick Wong, Apr 8, 2010
  7. usbseawolf2000

    usbseawolf2000 HSD PhD

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    That should give 18.5 volt. Motherboard should convert it to 12v and 3.3v for other components to run.

    You need to check at both points. You are right, it is better to start from the source (closest to the plug).
     
    #27 usbseawolf2000, Apr 8, 2010
  8. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    My first impression: Memory sounds bad.
     
    #28 a_gray_prius, Apr 8, 2010
  9. qbee42

    qbee42 My other car is a boat

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    Put the CPU back in. The BIOS can't run without the CPU. Nothing can run without the CPU.

    Tom
     
    #29 qbee42, Apr 8, 2010
  10. usbseawolf2000

    usbseawolf2000 HSD PhD

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    The BIOS looks for the CPU fan first. If it is not connected, it won't boot to protect the CPU. There are no warning from the BIOS about the missing CPU fan.

    BIOS can run Power On Self Test (POST) without CPU. This BIOS on this motherboard is not POSTing.
     
    #30 usbseawolf2000, Apr 8, 2010
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  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    OK, I am looking at the six pin wiring harness connector that comes from the power inlet.

    From one side to the other, here are the wire colors:

    1. Grey
    2. Black
    3. Tan
    4. White
    5. Red
    6. Red

    I assume that Black is ground. Between Black and either Red, I measure 19.94V.

    From Black to White, 0V.

    From Black to Tan, 19.21V.

    From Black to Grey, 0V.

    I suppose this means the motherboard is responsible for developing 5V and 12V?
     
    #31 Patrick Wong, Apr 8, 2010
  12. usbseawolf2000

    usbseawolf2000 HSD PhD

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    CPU and RAM normally runs at 3.3V. Laptop DVD and HD use 5V. Desktop HD, DVD, Floppy and fan use 12V. Laptop may not have 12V at all, after thinking about it.

    In a desktop power supply, PSU switch 3.3v, 5v, and 12v and supply to the motherboard. For laptop, the brick block supply only 18.5v (in your case) to the motherboard. The motherboard must be switching to 3.3v and 5v.

    I looked through the "Blink Codes" and it does not have anything listed for CPU fan missing. Desktop BIOS POST would warn for sure. Maybe HP BIOS does not have this kind of error beep.
     
    #32 usbseawolf2000, Apr 8, 2010
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    So, should I put it back together and save as a spare parts repository for the other HP laptop that I have?
     
    #33 Patrick Wong, Apr 8, 2010
  14. usbseawolf2000

    usbseawolf2000 HSD PhD

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    The motherboard is not displaying valid (documented) LED code. This leads me to believe the motherboard is bad. But you just got a replacement board (new?).

    gbarry may be right with this statement:
    Even if that's the case (bad CPU), the board should not be restarting continuously. This again leads to a bad motherboard.

    Can you still return the board?
     
    #34 usbseawolf2000, Apr 8, 2010
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I bought the replacement motherboard as an exchange, so I returned the original board in the same packaging. The replacement comes with a 90 day warranty.

    I don't know whether the replacement is "new" or "refurb".

    I've put everything back together now. It will not be a surprise to the group that there's no change in laptop behavior.

    I moved the two 2 GB memory modules, 4 GB total, to my other HP laptop. The memory works fine in that laptop and shows up as 4 GB when I look at "Properties" within Computer.

    Here's the latest: I called HP and the parts store agreed to allow me to return the parts for a full refund. So I am done with this tar baby. Thanks to all who tried to help me with this, but it's too much for me to deal with... :cool:
     
    #35 Patrick Wong, Apr 8, 2010
  16. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Is that other HP laptop AMD CPU also? I am thinking of swap testing with it.
     
    #36 usbseawolf2000, Apr 8, 2010
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, it also has an AMD CPU chip but they are not exactly the same type so I don't know if they are plug-compatible.

    Anyway, I found out that I can return the parts to HP for refund, see my edited msg above. Thanks for trying to help me with this.
     
    #37 Patrick Wong, Apr 8, 2010
  18. ursle

    ursle Gas miser

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    Pheww, good thing you wern't dealing with Tigerdirect, no returns..
    All's well that ends well
     
    #38 ursle, Apr 8, 2010
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