Blinking Amber Power Button on Precision 390

Discussion in 'Dell' started by W, Jan 27, 2014.

  1. W

    W Guest

    I have a Precision Workstation 390 with the power button blinking.
    According to Troubleshooting section, this means either a bad power supply
    or a failing system board.

    Is there any test that will help me isolate it further?
     
    W, Jan 27, 2014
    #1
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  2. W

    Ben Myers Guest

    Here's a visual test: Open up the case and inspect the motherboard for failed capacitors. A failed capacitor has either a bulging top or discoloration from leakage. One bad capacitor and the motherboard is history, not worth the repair.

    Here's a practical test: Disconnect the power supply from the motherboard and ALL devices. Take another known-good ATX12v 24-pin power supply with long enough wire leads, and connect it to the 24-pin and 4-pin connectors on the motherboard. Push power button to see what happens. if the board powers up to a BIOS screen, the original power supply has gone bad. If you getthe same blinking amber power button light, the motherboard has failed.

    Note that you do not need a power supply that is physically the same as theone in the 390 right now. The 24-pin and 4-pin power connectors are all that matters, because they are standard. And save yourself some time. Don't even remove the power supply from the 390. Just attach the other power supply from outside the chassis.

    Over the last several months, I got a number of systems from a local company that upgraded or replaced Precision 380, Precision 390 and Precision T3400 boxes, all with the same chassis and nearly identical power supplies. One or two had leaky capacitors. I have another T3400 motherboard in a case,awaiting testing (my time is limited, haven't gotten to it), and then a replacement power supply. I may take one from a Precision 380, 'cause the Core 2 Quad T3400 is a much better than a dual core 380... Ben Myers
     
    Ben Myers, Jan 27, 2014
    #2
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  3. W

    W Guest

    So here is an interesting result:

    1) First, it is a Precision 380 not 390

    2) Power supply is apparently good. But the strange result is that the
    system only blinks once you plug into the motherboard mini connector labeled
    "P2". If you only plug into the main motherboard connector, everything
    works. P2 is located in the vicinity of the CD ROM drive cage.

    What does P2 control, and what would this symptom mean? I'm guessing
    that P2 must power some fan like the CPU fan that is a discrete component?
    Perhaps the failure here is on that fan?

    --
    W



    Here's a visual test: Open up the case and inspect the motherboard for
    failed capacitors. A failed capacitor has either a bulging top or
    discoloration from leakage. One bad capacitor and the motherboard is
    history, not worth the repair.

    Here's a practical test: Disconnect the power supply from the motherboard
    and ALL devices. Take another known-good ATX12v 24-pin power supply with
    long enough wire leads, and connect it to the 24-pin and 4-pin connectors on
    the motherboard. Push power button to see what happens. if the board
    powers up to a BIOS screen, the original power supply has gone bad. If you
    get the same blinking amber power button light, the motherboard has failed.

    Note that you do not need a power supply that is physically the same as the
    one in the 390 right now. The 24-pin and 4-pin power connectors are all
    that matters, because they are standard. And save yourself some time.
    Don't even remove the power supply from the 390. Just attach the other
    power supply from outside the chassis.

    Over the last several months, I got a number of systems from a local company
    that upgraded or replaced Precision 380, Precision 390 and Precision T3400
    boxes, all with the same chassis and nearly identical power supplies. One
    or two had leaky capacitors. I have another T3400 motherboard in a case,
    awaiting testing (my time is limited, haven't gotten to it), and then a
    replacement power supply. I may take one from a Precision 380, 'cause the
    Core 2 Quad T3400 is a much better than a dual core 380... Ben Myers
     
    W, Jan 28, 2014
    #3
  4. W

    W Guest

    The power cable labeled P2 goes to a connector named 12VPOWER in the
    Precision 380 Quick Reference Guide.

    So with 12VPOWER connected, the front panel blinks an Orange light on the
    power button. NONE of the four green or amber diagnostic lights are powered
    on. Looks like some kind of short connected to that 12VPOWER?
     
    W, Jan 28, 2014
    #4
  5. W

    Ben Myers Guest

    Are you 1000% sure that the power supply is good? Is this the same power supply as the original? If so, you really and truly do need to test with another known good power supply. This is the only way to isolate with reasonable certainty whether the motherboard is bad or the power supply. (Well, there is very small chance that either CPU or memory is bad, but very unlikely.)

    That is EXACTLY what is running on my bench right now: A Precision 390 motherboard, video card, memory, flash stick with MEMTEST+ running, and a standard sized Antec power supply with all sorts of long connectors. The boardseems to be OK, so I need to get a power supply to complete a very nice Core 2 Quad system... Ben Myers
     
    Ben Myers, Jan 29, 2014
    #5
  6. W

    W Guest

    Sorry to top post, but my newsreader is not quoting correctly.

    Yes, we tested with a NEW power supply. Power to the main connector on
    the motherboard shows no error on the front light and the system starts to
    power on. As soon as the 12VPOWER on P2 is connected to the motherboard,
    we get the flashing amber light, duplicating exactly the symptom with the
    original power supply.

    And correction: we have a Precision 380 not a 390. They take the same
    power supply.

    And I would gladly send you our original one, but unfortunately it was
    destroyed in process of removal (someone cut cables to remove from the tight
    placement.

    Any idea on what the 12VPOWER on P2 is connecting to?

    --
    W


    Are you 1000% sure that the power supply is good? Is this the same power
    supply as the original? If so, you really and truly do need to test with
    another known good power supply. This is the only way to isolate with
    reasonable certainty whether the motherboard is bad or the power supply.
    (Well, there is very small chance that either CPU or memory is bad, but very
    unlikely.)

    That is EXACTLY what is running on my bench right now: A Precision 390
    motherboard, video card, memory, flash stick with MEMTEST+ running, and a
    standard sized Antec power supply with all sorts of long connectors. The
    board seems to be OK, so I need to get a power supply to complete a very
    nice Core 2 Quad system... Ben Myers
     
    W, Jan 29, 2014
    #6
  7. W

    Ben Myers Guest

     
    Ben Myers, Jan 29, 2014
    #7
  8. W

    micky Guest

    I think that's it. You've figured it out. The Quick Reference Guide is
    broken. Disconnect it and you'll be okay.

    Sometimes the QRG is printed on glossy paper and that can cause trouble.


    Also, whatever Ben says.
     
    micky, Feb 10, 2014
    #8
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