How to troubleshoot ATX power supply?

Discussion in 'Computer Support' started by Ron Holt, Mar 11, 2005.

  1. Ron Holt

    Ron Holt Guest

    I have an old computer that suddenly refuses to boot. When I power on
    the system there is no response, no fans, no beep codes, nothing. I
    suspect the power supply. It is an ATX 250 watt unit. How do I
    determine if the it works?

    Thanks,
    Otterspace
     
    Ron Holt, Mar 11, 2005
    #1
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  2. Stick it in another machine.
     
    =?ISO-8859-1?Q?R=F4g=EAr?=, Mar 11, 2005
    #2
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  3. Ron Holt

    elaich Guest

    The symptoms you describe are a pretty good indication that it's not
    working.

    They can be had dirt cheap on ebay these days. I bought one for $5.
    Granted, it was an el cheapo unit but it served it's purpose - verify that
    my old one is bad and serve as a temporary backup.

    ATX power supplies have logic circuitry in them and are not easily
    repairable. One thing you might do is pull the cover and look for a fuse.
    Keep in mind that a blown fuse is indicative of a problem.
     
    elaich, Mar 11, 2005
    #3
  4. Actually, before I'd do that, I'd take out all expansion cards,
    disconnect all drives from their data and power cables and see if that
    helps. Then you have it narrowed down to motherboard, processor, memory
    and power supply if it doesn't show signs of life.

    It's not that unusual for some component you'd hardly think of to cause
    that sort of behavior.
     
    =?ISO-8859-1?Q?R=F4g=EAr?=, Mar 11, 2005
    #4
  5. Ron Holt

    Vanguard Guest


    Got a voltmeter?
     
    Vanguard, Mar 11, 2005
    #5
  6. Ron Holt

    Barry Guest

    If your machine is pluged into a surge protector, make sure it hasn't gone
    bad,,,
     
    Barry, Mar 11, 2005
    #6
  7. Ron Holt

    Lookout Guest

    How old? Maybe the bios battery has died?
     
    Lookout, Mar 11, 2005
    #7
  8. Ron Holt

    Toolman Tim Guest

    Huh? The BIOS battery being dead will not prevent the fans, lights, HD, etc.
    from powering on...
     
    Toolman Tim, Mar 12, 2005
    #8
  9. Ron Holt

    Vanguard Guest


    Actually from a discussion in the alt.comp.hardware group, Koni, a user
    that has exhibited exceptional expertise in his posts, has indicated
    that a dead CMOS battery can prevent a system from booting up. I had
    not ever seen this so I asked him to test again. He still had a test
    motherboard from a customer (where he replaced their mobo so he had the
    old one) where the dead battery prevented booting up. After he found it
    and tested again, yep, it would not boot up with a dead battery but
    would boot with a good battery. See http://snipurl.com/ddtm.
     
    Vanguard, Mar 12, 2005
    #9
  10. Ron Holt

    Toolman Tim Guest

    I certainly wouldn't argue with that, knowing that the power on function of
    the motherboard could be affected, but it seems to be a rather isolated
    problem. I've not ran into that with any motherboard I've worked with, but
    obviously the board model in that discussion has shown itself to be fussy
    about the battery. I've have a lot of boards with button batteries totally
    missing that would still POST, although they may not boot until the CMOS
    settings were all corrected.
     
    Toolman Tim, Mar 12, 2005
    #10
  11. Ron Holt

    Plato Guest

    I like some of the new mobos where the cr2032 battery is in verticle to
    make it way easier to replace.
     
    Plato, Mar 12, 2005
    #11
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