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  1. #1
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    No electrical response to starting desktop compter

    Here's the scenario, short version... Start with homebuilt i7-2660K desktop that works fine electrically (and otherwise).

    - computer electrical cord from 120v outlet, Seasonic 650W PSU switch off
    - other outlet in same receptacle has electrical cord running to 6-oulet distributor, with other components plugged in
    - there's a power surge during voltage testing of one distributor outlet and breaker kicks
    - after restoring power, computer (not moved) won't start electrically, but other components plugged into outlet and another distributor do
    - same no response in another room (only power cord attached)
    - shorting the PSU (paper clip test) gets its fan running (peripherals unplugged from PSU)

    Question: Why won't the computer start electrically?

    Any ideas? Thanks

  2. #2
    3 Star Lounger bassfisher6522's Avatar
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    Seasonic 650W PSU switch off
    Well, from your quote, did you turn the PSU power switch to the on position?

  3. #3
    Silver Lounger RolandJS's Avatar
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    If power supply on and working, then you might have mobo and/or attached to mobo item short.
    "Take care of thy backups and thy restores shall take care of thee." Ben Franklin revisited.
    http://collegecafe.fr.yuku.com/forum...-Technologies/

  4. #4
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    Your reply raises two questions I've been wondering about:

    - if the PSU was off, how could something past it in the cirucit have been affected?
    - if there's a short down the line, wouldn't there be at least some momentary discernable electrical response to starting the computer - unless the front panel start switch itself were destroyed?

    The only things that possibly would have been on at the time of the power surge from just being plugged into the distributor would have been a router and cable box. Everything else - dac, monitor, powered speakers - were switched off.
    Last edited by highstream; 2015-04-30 at 11:56.

  5. #5
    Silver Lounger RolandJS's Avatar
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    Dunno about modern stuff; back in Fred Flintstone computer days, some computers would not even give any sign of life if a short existed. And, my memory may be faulty, highstream, you might be right as rain
    What happens if you do a power supply & motherboard fire-up?
    "Take care of thy backups and thy restores shall take care of thee." Ben Franklin revisited.
    http://collegecafe.fr.yuku.com/forum...-Technologies/

  6. #6
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    First suspect is the PSU. Second is the motherboard.
    Sometimes though when a PSU goes it takes the motherboard with it.

    rstew

  7. #7
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    Thanks for your replies. Had someone look at it and he reports the PSU is fine, but noticed that the mobo as a burn spot near the USB busses and that further testing shows the board is bad ("spectacularly"). I'm still not sure how that happens when the PSU switch is off, but forgot to mention that all the peripherals were still connected - USB, printers, keyboard - but also an LPS was plugged into the distributor with a power line to the USB card.

  8. #8
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    Quote Originally Posted by highstream View Post
    ....the mobo as a burn spot near the USB busses and that further testing shows the board is bad ("spectacularly"). I'm still not sure how that happens when the PSU switch is off, ....
    Presumably a power surge that made its way through the PSU (which should not happen) while unattended and "off" taking out the MB. Possibly came through an AC powered, PC attached USB device instead of the PSU and that is why it is localized in the area of the USB controller.

    Test everything including peripherals afterwards. If you are replacing MB only it will have to support the CPU and RAM. If this is an OEM Windows install the license is reusable under the repair paragraph exception in your EULA.

  9. #9
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    Yes, I think the live LPS with a power line to the USB audio card is likely the culprit. The person who checked the mobo for me also checked the peripherals and said they were ok. The unfortunate part is that my i7-2600K is hardly surpassed by current models without spending a bundle, but it's an 1155 series and decent Z97 mobos now are 1150, so I had to put out for an i5 (4690K). I had purchased the regular Win 8 Pro x64 cheap when it came out, so I'm ok there. But this will be the second clean reinstall of Win 8.1 in the past five months. C'est la vie...

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