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PSU Help required with non-powering PC

Discussion in 'Hardware' started by Bauul, 28 Jun 2009.

  1. Bauul

    Bauul Sir Bongaminge

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    Ok, so yesterday I installed a brand new Sapphire 4770, which I was having a fair bit of trouble with (see this thread for details).

    In brief, the card just wasn't performing as well as it should have been. It was suggested it may have been the PSU, but I recokened a 450W with two 18amp 12V rails should have been enough (and I was hardly overloading the system).

    So, I thought it might have been a driver issue. My previous card was a 7900GT, so I went through safe mode to remove all the old drivers with Driver Sweeper. It left nTune in, so I was manually removing the remnents of the application in the Registry Editor when POOF... off goes the PC.

    There's still some life left in it, with it all plugged in the Capslock light still works and the Motherboard LED lights up, but upon pressing the power button it boots up for prehaps a milisecond, and then switches itself off again. The Capslock light etc. still work, but it won't turn on again. Switching it off and on at the back switch resets this, but doesn't improve anything.

    I tried disconnecting the new GPU and every possible periphery, no difference. I presume it's the PSU and I need a replacement, but before I splash £50 out on a new one, has anyone got any ideas as to what else it might be?

    My full system spec is:
    CPU: Pentium 4 CPU 3.4 Ghz | RAM: 1Gb + 2x512Mb Corsair DDR2 667 Mhz | HDD: WD Raptor 36Gb, Seagate 300Gb | MB: Asus P5LD2 SE | PSU: FG ATX-450PAF (450W, dual 12V rails at 18amps each)

    + an old 7900GT or a new Sapphire 4770 depending.

    Any help would be really appreciated! :waah:
     
    Last edited by a moderator: 28 Jun 2009
  2. MrWillyWonka

    MrWillyWonka Chocolate computers galore!

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    So your PC didn't really explode? Next time please use an appropiate title reflecting the thread.
     
  3. pistol_pete

    pistol_pete Air Cooled Fool

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    Short circuit?

    Otherwise, no ideas!
     
  4. Bauul

    Bauul Sir Bongaminge

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    But over the top titles are a hallmark of "help" threads!

    Alright, point taken. You know how it is though when things go belly up and there's no-one around to complain to.

    So, after doing some research, action points for now will be:
    • Check Motherboard for damaged capacitors
    • Check its not the power button being funny
    • Clean everything
    • Leave for a day and then try again

    Edit: I got it to turn on! Once! And then it hasn't done it since. Maybe it is a short circuit, but where do I even start looking for one?
     
    Last edited: 28 Jun 2009
  5. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    It's a pain in the ass, but remove everything form the case and lay it on the floor. Still power on? Put everything back!
     
  6. thehippoz

    thehippoz New Member

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    agree with pedro.. take it all out the case and that will eliminate grounding issues- but the floor part I'm not too keen on!
     
  7. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Well, I've got laminate flooring, but I guess a table or some cardboard would probably be better than carpet.

    Oh, well don't step on it too! (I do all my builds on the floor however, I just find it easier, more comfortable and it's great to have so much more room than a table.)
     
  8. thehippoz

    thehippoz New Member

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    ah thought you meant carpet.. I've seen that alot on youtube.. guy buys a new graphics card and has it on a bed/carpet right before install :clap: think that's why nvidia started encasing them in plastic
     
  9. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Yeah, static discharge is bad, m'kay!
     
  10. Bauul

    Bauul Sir Bongaminge

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    Alright, tonight I'll strip it all apart and do my best not to break it in the process. Wish me luck! :)

    Edit: Been chatting with a guy in the IT department who insists it's probably a tanked PSU. He was reckoning I need at least a 650W PSU to attempt to run the card and all the extras. That seems rather a lot to me. Rekcon he has a point or if I do need a new PSU would something like the 500W OCZ ModXStream Bit recommends in the Hardware Guide be sufficient?
     
    Last edited: 29 Jun 2009
  11. Bauul

    Bauul Sir Bongaminge

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    Turns out it may well have neen a short circuit. I took the whole thing apart and voila, it worked! Been slowly piecing it back together again and so far have nearly everything installed.

    Only down side is now Windows is insisting on a reactivation (I flashed the BIOS as part of my diagnosis), so I need to lug the whole thing over the router to plug it in and access the net. After everything, the last thing I expected to hold things up was Windows!
     
  12. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    You can do it over the phone, if that's easier.
     
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