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Solved Power Supply question

Discussion in 'Hardware' started by bubbanorth, Nov 9, 2019.

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  1. bubbanorth

    bubbanorth Thread Starter

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    Computer won't boot, no noises, no beeps.

    When the computer is plugged in, should I get voltage between the yellow and black wires?

    Other connectors I've looked at seem normal ( 3.3, 5 or 12v ) IMG_20191109_151230911.jpg IMG_20191109_151425496_HDR.jpg

    2nd picture shows where this plugs into motherboard - H-RS880-uATX (Aloe)

    Thanks for reading, and thanks in advance.
     
  2. bassfisher6522

    bassfisher6522

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    What the 2nd photo is showing, looks like the CPU power port. That needs to be plugged in or you risk damaging the CPU and/or mobo.
     
  3. Macboatmaster

    Macboatmaster Trusted Advisor Spam Fighter

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    Last edited: Nov 9, 2019
  4. bubbanorth

    bubbanorth Thread Starter

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    Hey Macboatmaster, thank you for the info.
    - "the PSU is turned on by connecting pins on the main power connection"
    I think this means green to black on the 24 pin connector?
    Okay, so with green to black on the 24 pin, I get 11.86v yellow on that 4 pin connector, not quite 12v.
    Thanks.

    My current suspect is a bad power button ( I have 3.3, 5 and 12v on all the non black pins on the 24 pin connector when green is grounded ).

    For the pictures, I have read that I can by-pass the power button by shorting two of these pins, ( the wire goes to the power button ), but there does not seem to be a usable layout published for this motherboard.
    From youtube it seems that if I short the pins for the black and red wires that should act like power button on, but I can't be sure because of the lack of documentation. Anyone know which pins to short to bypass power button - H-RS880-uATX (Aloe).
    Thank you to all.
    IMG_20191109_233223733.jpg IMG_20191109_233012716.jpg
     
  5. Macboatmaster

    Macboatmaster Trusted Advisor Spam Fighter

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    What is the actual FULL MODEL details of the HP computer
    Do NOT reply on YouTube it is often wrong, especially if you are watching something that is not for your actual model
    I have sent you the link to your board but it is difficult to identify the front panel header on the diagram
    You short the pins usually headed POWER SWITCH on the front panel header
    I think you will find yours is labelled + and - and are opposite those labelled RESET SW

    you only short these briefly not leave connected like you to turn it on
    If you look at the link I sent you then expand motherboard layout you can see it is diffivult to determine which is which
    However on the manual for the actual model it should be clearer
     
  6. bubbanorth

    bubbanorth Thread Starter

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    Macboatmaster, thank you so much for your help.
    The computer is:
    HP Pavilion p6218f
    prod #: AU993AA-ABL
    https://support.hp.com/ca-en/produc...p-pc-series/3999459/model/4057527?sku=AU993AA
    H-RS880-uATX (Aloe)
    I have not been able to find a proper manual/diagram for the motherboard, and have come across many posts complaining that it is not available. There are a few dead links to manuals ( built in 2009 ).

    I did a continuity test on the power switch wire, red + black was the only combo that showed no resistance, it corresponded with this diagram:
    download.jpg
    so I went ahead and shorted 6 and 8 ( red and black for me ). Still no signs of life, no beeps, no fans, no sounds. ( I don't have wires for the reset switch )

    To summarise,
    24 pin connector gives 3.3, 5, and 12 ( power supply okay? )
    power switch seems okay, no resistance red+black when button pressed
    shorted 6 and 8 on front panel header - no life
    therefore dead motherboard????

    Should I go ahead and look for a motherboard now, or are there more tests I should try?
    Thank you so much.
     
  7. Macboatmaster

    Macboatmaster Trusted Advisor Spam Fighter

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    Without even a fan running unless they are all wired to headers and temp controlled and MORE IMPORTANTLY without even the buzzer sounding which is above the main power connection and sounds error beeps, one would suspect a major fault on the board or the PSU
    The fact that you get voltage on as multimeter does not mean that the PSU works on load
    Although that is a basic test, a PSU can fail under load

    I would disconnect all external connections, monitor, keyboard, mouse etc and then with case open see again if you get any error beeps on the buzzer
    If that does not show anything I would take out ram and again check for error beeps

    If still no result and there is no history to this - for example previous unexpected shutdowns etc. and you have available a local computer repair business, not one of the giant multiples, then I would take out power supply and ask them to test.
    It should not cost more than a few £/$ and may just save you the cost of a board to find it is the PSU - showing OK on voltages with multimeter but failing under load

    When you shorted Power On to ground on 24pin DID the PSU fan NOT start
    It should do
     
    Last edited: Nov 11, 2019
  8. bubbanorth

    bubbanorth Thread Starter

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    Macboatmaster, thank you so much for your help.
    Took the PC to a small shop, they plugged in a portable analyzer into the 24 pin connector, powered up the PSU and determined it was flaky.
    Bought a new PSU, plugged it in and the computer has come to life.
    As a side note, the led on the motherboard no longer has a slight flicker.
    Thank you. I should be up and running shortly.
     
  9. Macboatmaster

    Macboatmaster Trusted Advisor Spam Fighter

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    Pleased to have helped
    Let us know how it goes
    When all is OK mark the topic solved please
    Click mark solved on your opening post
     
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