What are the chances of receiving a new defective power supply.

Discussion in 'Computer Support' started by Ozark, Nov 10, 2007.

  1. Ozark

    Ozark Guest

    Hi Guys,

    I'm trying to get my girl friend's computer up and running. I'm
    dealing with an HP 8765C. A few weeks ago I turned it on and it made a
    loud pop. After that attempting to start the unit resulted in no
    response. I made sure my UPS was putting out power etc.

    I did a little research and the popular consensus was that the power
    supply had died. I checked the power supply by jumping the green and
    black wires on the mother board connector. Nothing happened (no fan)
    indicating a dead power supply.

    I ordered a new Thermaltake power supply, installed it and again
    nothing happened. I tested it according to Thermaltake instructions.
    Same thing, nothing happened.

    This is my first time at dealing with a dead power supply. It seems
    unlikely that I would get a dead one right out of the box. Am I
    overlooking something? Any advice would be appreciated.

    Thanks

    Don
     
    Ozark, Nov 10, 2007
    #1
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  2. Ozark

    Mike Easter Guest

    Troubleshooting the hardware problems which include the mobo and PS need
    to be done very very carefully, or you will misdiagnose.
    This is the part where you need to prove what you did to prove that.
    You aren't done yet.
    Having a 'spare' PS is a good thing to already have when you are at
    troubleshooting step 1 above.

    There are a lot of good sites. Here's an example of a 'pretty'
    flowchart graphic and some useful words as well
    http://www.fonerbooks.com/power.htm Flowchart for ATX Power Supply
    Repair

    Those guys are trying to sell a book. Some people like what you find at
    pcguide http://www.pcguide.com/ts/x/comp/power.htm Troubleshooting
    Power Sources and Power Protection Devices

    .... plus pcguide is great for a lot of PS fundamentals in a different
    section.
     
    Mike Easter, Nov 10, 2007
    #2
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  3. Ozark

    Ozark Guest

    Thanks Mike,

    I appreciate the info.
     
    Ozark, Nov 10, 2007
    #3
  4. Ozark

    Pennywise Guest

    Loud pop, look for a blown capacitor.
     
    Pennywise, Nov 11, 2007
    #4
  5. Ozark

    w_tom Guest

    Is popular consensus based on technical knowledge or just what is
    easiest to replace?

    The power supply system is more than just a power supply. Do you
    keep replacing parts until something appears to work? That is called
    shotgunning - what is common among the 'popular consensus'. If a car
    mechanic diagnosised that way, he would be quickly unemployed. In
    but two minutes, you could have known what is bad using the procedure
    in "When your computer dies without warning....." starting 6 Feb
    2007 in the newsgroup alt.windows-xp at:
    http://tinyurl.com/yvf9vh

    Especially important in your case are numbers from the green, gray,
    and purple wires before and when power switch is pressed.

    Popular consensus says the green to black wire jumper identified a
    power supply good or bad. First, some supplies will not start this
    way without a load. That is unique to each power supply design.
    Second, a power supply can still be defective and yet power when
    disconnected from computer and using that green to black wire jumper.
    The jumper can only provide a 'maybe' answer.

    The only useful answer is one that provides a definitive answer.
    That is the multimeter, disconnecting nothing, and two minutes.

    Finally, the procedure also provides numbers. Your replies will
    only be as good as the information provided. To get more useful
    replies from those who actually know what is inside the entire power
    supply 'system', post those numbers here.

    Demonstrated is the meaning of a popular phrase, "Don't work harder;
    work smarter".
     
    w_tom, Nov 11, 2007
    #5
  6. Ozark

    theokochen Guest

     
    theokochen, Nov 11, 2007
    #6
  7. Ozark

    Evan Platt Guest

    <Nothing for the 100th time.>

    *plonk*
     
    Evan Platt, Nov 11, 2007
    #7
  8. Ozark

    Ozark Guest

    Thanks for the helpful reply. I'll take some measurements and post
    them.
    For what it's worth, I have spent about seven hours or so researching
    this problem and this is the first time anyone has pointed my in this
    direction. The vast majority of the places I have checked including
    the manufacturers' site just suggest jumping the green and black and
    watching the PS fan.
     
    Ozark, Nov 11, 2007
    #8
  9. Ozark

    R T Guest

    | Hi Guys,
    |
    | I'm trying to get my girl friend's computer up and running. I'm
    | dealing with an HP 8765C. A few weeks ago I turned it on and it made a
    | loud pop. After that attempting to start the unit resulted in no
    | response. I made sure my UPS was putting out power etc.
    |
    | I did a little research and the popular consensus was that the power
    | supply had died. I checked the power supply by jumping the green and
    | black wires on the mother board connector. Nothing happened (no fan)
    | indicating a dead power supply.
    |
    | I ordered a new Thermaltake power supply, installed it and again
    | nothing happened. I tested it according to Thermaltake instructions.
    | Same thing, nothing happened.
    |
    | This is my first time at dealing with a dead power supply. It seems
    | unlikely that I would get a dead one right out of the box. Am I
    | overlooking something? Any advice would be appreciated.
    |
    | Thanks
    |
    | Don

    When assembling a computer, attaching power cable to floppy drive, it
    sometimes happens that plug is misaligned, connecting only two of the three
    pins.. This will fry the PSU (but may not result in a loud pop).
     
    R T, Nov 12, 2007
    #9
  10. Ozark

    w_tom Guest

    No load must damage a properly designed supply. Even the earliest
    Intel specs for power supplies listed a minimum size for the wire to
    short together all outputs - and no damage. However with so many
    computer assemblers who do not even know how electricity works, then
    some manufactures have even increases profits by 'forgetting' to
    include essential functions inside that supply.

    If a misguided power connector causes a power supply failure, then
    the damage is directly traceable to a misguided human. These power
    supply requirements of no damage were standard long before PCs even
    existed.

    How poor is electrical knowledge among the 'computer literate'?
    Even an A+ Certified Computer Tech need not know how electricity works
    to be certified - need not know what has long been standard for power
    supplies..
     
    w_tom, Nov 13, 2007
    #10
  11. Ozark

    nobody > Guest

    It's very possible that you have one or more blown capacitors on the
    motherboard. Look for metal cans with shrink-wrap labels, and if the end
    shows a crusty deposit or is actually blown open... that's your problem.
     
    nobody >, Nov 13, 2007
    #11
  12. Ozark

    Ozark Guest

    That can't be a good thing! :( I'll take a look at it tomorrow. If
    the mother board is kaput I suppose I can't complain too much. We have
    been using this computer for seven years or so and this is the first
    mechanical failure.

    I still need to dig out my voltometer and check the output of the PS.
    It gets dark so darn early I have a hard time finding anything in my
    tool shed.

    Thanks
     
    Ozark, Nov 14, 2007
    #12
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