Diagnosing Power Supplies

Discussion in 'A+ Certification' started by Dave Hardenbrook, Apr 17, 2005.

  1. Thanks to those who answered by question about mixing ATX and Micro-ATX
    Power supplies and Mobo's. I have a few follow-up questions. When I
    tested my client's MicroATX Mobo with a Full ATX Power supply, the Mobo
    came to life on startup, which makes me suspect her Power Supply is
    dead. However, this is the second Power Supply in a row that has died
    on her in the last few months -- The current one I installed in
    November. Is it probable that a new Power supply could tragically
    drop dead so young?

    I would like to use a multimeter to determine for certain, but I can
    find no definitive guide for using one to test a Power Supply. Mike
    Meyers goes into it in his A+ "All-in-One" guide, but he leaves out a
    few details, like where the leads need to be plugged in on the
    multimeter, whether the system needs to be powered on during the
    test(!), and exactly what part of the wires on the connector the leads
    need to be touching (do they have to be touching metal?). Armed with a
    newly purchased $10.00 one from MicroCenter, I tried to follow his
    instructions to the best of my ability, but registered zero, even when
    testing a known working system, while it was powered up! I don't feel
    confident enough about fiddling with electricity to proceed without
    being absolutely certain of what I'm doing, so I'd appreciate some
    guidance. (Could the *multimeter* be defective???)

    Another clue in this mystery I'm struggling to interpret: My client
    complains that her system had a hint of that "burnt rubber" smell in the
    period between my installing the current Power Supply five months ago
    and her system going dead this week, even though her system seemed to
    work fine in that period. Could a faulty Power Supply have degraded her
    Mobo to the point that it smelled burnt, but still functioned?
    FWIW, I don;t detect what I'd descrive as a true "burnt" smell -- It has
    only a faint, nondescript aroma such as I have detected on known working
    Mobo's. Also, when I look at my client's Mobo, I see no sign of it
    having been "cooked". But perhaps if I could successfully power it up
    for a period, I would detect the "burning" smell my client describes.
    Could defects in the last two Power supplies have resulted in a
    "medium rare" Mobo that still works, possibly with degraded performance,
    but not "well done" enough to fail outright, at least not *yet*...?

    Final question: I have heard about faulty Power Supplies "killing"
    Mobo's. Is the reverse possible, and that a subtle defect in my
    client's Mobo could be "murdering" every Power Supply I connect it to?

    Any insight the gurus can offer this young grasshopper would be greatly
    appeciated.

    --
    Dave
     
    Dave Hardenbrook, Apr 17, 2005
    #1
    1. Advertising

  2. In article <Haw8e.4637$>, eelder1
    @tampabay.rr.com says...
    > At this point, a UPS may be in order. How many watts was the PS you
    > replaced, rated at?


    250W, which was the highest wattage I could find for a MicroATX PS.
    Her previous one was 150W. And as it was she complained about the
    higher-powered one being "too loud". Is a UPS or at least a really
    decent Surge Suppressor the best solution?

    --
    Dave
     
    Dave Hardenbrook, Apr 18, 2005
    #2
    1. Advertising

  3. Dave Hardenbrook

    w_tom Guest

    First lets eliminate those silly myths. Neither the UPS nor
    a plug-in surge protector is a solution. Those are too often
    promoted by myth purveyors that cannot even say (with numbers)
    what those devices do.

    More myths to confront. Reverse wires on AC receptacle will
    not cause power supply failure. That outlet tester would be
    wasted money. Anything that the outlet tester could report is
    reported - and more - by the multimeter.

    Another myth about ground rods - missing or existing -
    would have nothing to do with power supply operation. Those
    with basic electrical knowledge would know this.


    Hopefully the multimeter is digital. If using an analog
    meter, the readings will be insufficient. The meter should
    have a ohms scale or conductivity measuring circuit. Put
    meter in those modes and touch leads together. Meter should
    read 0.

    Now to determine what is coming out of power supply. Put
    the meter in DC volts. Use this procedure to measure the
    +5VSB (measure purple wire to black wire). This 5 volts
    should exist when AC cord is connected AND when power supply
    is both on and off. Procedures to use meter on a power supply
    are described in two posts: "Computer doesnt start at all"
    in alt.comp.hardware on 10 Jan 2004 at
    http://tinyurl.com/2t69q and
    "I think my power supply is dead" in alt.comp.hardware on 5
    Feb 2004 at
    http://tinyurl.com/yvbw9

    A power supply properly constructed will never burn out
    motherboards. The power supply must provide specs and must
    specifically list over voltage protection. Furthermore, you
    can short together all outputs from a power supply and that
    supply still must not be damaged. Same applies to
    motherboard. The motherboard also cannot damage a properly
    constructed supply. But again, those supplies not provided
    with a long list of numeric specs are often missing these and
    many other standard and necessary functions.


    Dave Hardenbrook wrote:
    > Thanks to those who answered by question about mixing ATX and Micro-ATX
    > Power supplies and Mobo's. I have a few follow-up questions. When I
    > tested my client's MicroATX Mobo with a Full ATX Power supply, the Mobo
    > came to life on startup, which makes me suspect her Power Supply is
    > dead. However, this is the second Power Supply in a row that has died
    > on her in the last few months -- The current one I installed in
    > November. Is it probable that a new Power supply could tragically
    > drop dead so young?
    >
    > I would like to use a multimeter to determine for certain, but I can
    > find no definitive guide for using one to test a Power Supply. Mike
    > Meyers goes into it in his A+ "All-in-One" guide, but he leaves out a
    > few details, like where the leads need to be plugged in on the
    > multimeter, whether the system needs to be powered on during the
    > test(!), and exactly what part of the wires on the connector the leads
    > need to be touching (do they have to be touching metal?). Armed with a
    > newly purchased $10.00 one from MicroCenter, I tried to follow his
    > instructions to the best of my ability, but registered zero, even when
    > testing a known working system, while it was powered up! I don't feel
    > confident enough about fiddling with electricity to proceed without
    > being absolutely certain of what I'm doing, so I'd appreciate some
    > guidance. (Could the *multimeter* be defective???)
    >
    > Another clue in this mystery I'm struggling to interpret: My client
    > complains that her system had a hint of that "burnt rubber" smell in the
    > period between my installing the current Power Supply five months ago
    > and her system going dead this week, even though her system seemed to
    > work fine in that period. Could a faulty Power Supply have degraded her
    > Mobo to the point that it smelled burnt, but still functioned?
    > FWIW, I don;t detect what I'd descrive as a true "burnt" smell -- It has
    > only a faint, nondescript aroma such as I have detected on known working
    > Mobo's. Also, when I look at my client's Mobo, I see no sign of it
    > having been "cooked". But perhaps if I could successfully power it up
    > for a period, I would detect the "burning" smell my client describes.
    > Could defects in the last two Power supplies have resulted in a
    > "medium rare" Mobo that still works, possibly with degraded performance,
    > but not "well done" enough to fail outright, at least not *yet*...?
    >
    > Final question: I have heard about faulty Power Supplies "killing"
    > Mobo's. Is the reverse possible, and that a subtle defect in my
    > client's Mobo could be "murdering" every Power Supply I connect it to?
    >
    > Any insight the gurus can offer this young grasshopper would be greatly
    > appeciated.
     
    w_tom, Apr 18, 2005
    #3
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Silverstrand

    Modular Power Supplies @ A True Review

    Silverstrand, Jun 28, 2005, in forum: Front Page News
    Replies:
    2
    Views:
    786
    unholy
    Jun 29, 2005
  2. Silverstrand

    HEC Power Supplies @ ThinkComputers.org

    Silverstrand, Jul 17, 2005, in forum: Front Page News
    Replies:
    2
    Views:
    831
    zachig
    Jul 20, 2005
  3. =?Utf-8?B?SlA=?=

    Power supplies

    =?Utf-8?B?SlA=?=, Nov 9, 2003, in forum: Microsoft Certification
    Replies:
    4
    Views:
    525
    Larry Samuels MS-MVP XP \(Shell/User\)
    Nov 15, 2003
  4. Silverstrand

    Beginners Guides: Diagnosing Bad Memory

    Silverstrand, Apr 21, 2006, in forum: Front Page News
    Replies:
    0
    Views:
    748
    Silverstrand
    Apr 21, 2006
  5. Diagnosing a dead computer

    , Oct 29, 2005, in forum: Computer Information
    Replies:
    10
    Views:
    932
    'My Name
    Nov 23, 2005
Loading...

Share This Page