Power Supply vs. Motherboard

Discussion in 'A+ Certification' started by smackedass, Feb 20, 2007.

  1. smackedass

    JohnO Guest

    Apparently CompTIA's surveys of the computer repair industry didn't
    identify electronics as a skill needed by *entry-level* technicians.
    Clearly it's a skill that's invaluable for experienced techs.

    -John O
     
    JohnO, Feb 22, 2007
    #21
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  2. smackedass

    SBFan2000 Guest

    Don't worry about whether or not they think you learned anything. One sure
    truth around here is that most think they know everything and are unwilling
    to accept other views and/or ideas. There are also plenty that seem to
    love to deal with absolutes as in "always" and "nevers" which are seldom
    correct. From time to time we all think we have the 100% answer and forget
    that great saying "A true wiseman asks more questions than he has answers"
     
    SBFan2000, Feb 23, 2007
    #22
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  3. smackedass

    SBFan2000 Guest

    Get a job working on copiers. I've never learned so much about electronics
    and electromechanical systems so fast! :)
     
    SBFan2000, Feb 23, 2007
    #23
  4. smackedass

    w_tom Guest

    The power supply tester reports what a paper clip will report - that
    power turns on. Nothing more. Power supply tester does not and
    cannot report the supply is good or in spec. A major load (ie
    computer) is required to report that. Meanwhile the 3.5 digit
    multimeter does just that - and reports numbers that can provide other
    useful information in replies. Power supplies that fail under load -
    ie connected to a computer - may work just fine on a power supply
    tester or with the paper clip. But the meter - and without
    disconnecting anything - finds the failure (and future failures)
    immediately. Meter can report a power supply in spec. Power supply
    tester obviously cannot. No load means no valid test.

    Power supply tester can only report a power supply as defective; it
    cannot report the power supply as good. The meter - what informed
    techs use - will report power supply as either defective or good. A
    power supply tester that does not report both possible conditions is
    only reporting what a paper clip also discovers.

    Meanwhile a more than sufficient 3.5 digit multimeter sells for $20
    in Lowes, Radio Shack, K-mart, Sears, and Home Depot. Often meters
    sell on sale for $10. Michael should have known this. Instead he
    would waste $8 on a power supply tester that only reports what a paper
    clip also does - cannot report a power supply as good - does not
    provide numbers that can also report other useful facts.

    Ignore hype for a power supply tester marketed to those who want to
    'buy solutions' rather than learn. A $20 meter that reports faster
    and without disconnecting is also a necessary tool for solving other
    electrical problems - including other and future power supplies that a
    power supply tester cannot test. Get a meter and don't even look
    back.

    Power supply tester cannot report a power supply as good. Meter
    reports power supply as either bad or good. A technician needs to know
    both. Same money results in a more useful tool - the meter. Properly
    informed techs use the meter. Properly informed techs also know good
    3.5 digit multimeter are routinely sold for $20 - and less - not $50.
     
    w_tom, Feb 23, 2007
    #24
  5. smackedass

    SBFan2000 Guest

    Does not a power supply tester verify that the voltages are correct? The
    only one I ever saw had leds that would lite if the rail had the correct
    voltage, or am I thinking of something else. Multimeters are necessary and
    thats what I use but they can only report what is currently on the line.
    (as does the PS tester I've seen) Most PSs I've seen that were causing
    problems "here and there" were because the voltages would go out of spec for
    a few seconds or less. (peaks and dips) The only way to catch that is to
    look at the PS under load and over a longer period. That is unless your
    lucky enough to have the meter on at just the right time to catch the
    fluctuation.
     
    SBFan2000, Feb 23, 2007
    #25
  6. smackedass

    JohnO Guest

    Exactly. That's why someone mentioned oscilloscopes and fluctuating
    loads to *properly* test a PS. You can find some problems with a
    meter, IF you have a solid grasp of Ohm's Law, AND you have a fair
    amount of experience watching PS voltages and know what "looks right"
    and "looks wrong."

    w_tom is only wrong on one point...that entry-level techs (A+) have
    the ability to use a meter to analyze a PS problem. The computer
    industry says they don't need that, and as a result very few IT
    training programs include electronics. And maybe he's off on one other
    thing...when buying a meter the inexperienced tech needs a meter that
    can tolerate a mistake, and not blow up with the first bad connection
    to an AC circuit. I've been involved in the electronics training
    industry for 15 years, and new techs will blow up cheap meters. One
    other thing I just remembered....cheap meters don't have fast enough
    sampling rates to see supply fluctuations. You need a good one for
    that.

    -John O
     
    JohnO, Feb 24, 2007
    #26
  7. smackedass

    SBFan2000 Guest

    I was going to say, mine cost me $80. I use it all the time but it has so
    many features that there are things that I've never used!
     
    SBFan2000, Feb 24, 2007
    #27
  8. smackedass

    w_tom Guest

    Even a $20 meter will measure voltage just fine. No meter (except
    the most expensive) will measure ripple voltage. But that number is
    including in these limits: 3.23, 4.87, and 11.7. These numbers take
    Intel specs, include ripple voltage, and how meters measure. Any
    voltage that is below those numbers should be considered bad. Without
    a load, the power supply tester would measure that same voltage as
    good.

    Furthermore the numbers, when posted, can result in further useful
    information. For example, one voltage extremely low and another at a
    highest limit also suggests problems.

    A power supply tester, without that power supply connected to a full
    load, can only report the supply as bad or as unknown. Without a
    load, we still don't know if the power supply is good. What is a best
    load? That computer while multitasking to all peripherals. How do we
    test a power supply when it is connected to a full load of
    peripherals? The multimeter.

    Power supply tester cannot report a power supply as good because it
    does not test the supply under load. A $20 meter can perform that;
    report the power supply AND the rest of a power supply 'system' as
    good. Yes, we are not just testing a power supply. We must test the
    entire 'power supply system'. Just another thing that power supply
    tester cannot do. Power supply tester also does not provide numbers.

    Is power supply sufficiently sized for the load? Again, the power
    supply tester cannot say. But again, a 3.5 digit multimeter will
    detect a power supply that is too small. Get and use the meter - and
    don't even look back.
     
    w_tom, Feb 24, 2007
    #28
  9. smackedass

    Patty Guest

    One thing that I was advised to buy was a "POST card". It can be inserted
    into the PCI slot of a questionable motherboard and will give you the post
    codes as to what's going on during the boot process. The one I have also
    has LED lights that are supposed to tell you if the power supply is
    supplying all the necessary voltages to the motherboard. I believe they
    cost somewhere around $40 or so.

    I also have a multimeter which I use for all sorts of things, even checking
    battery strength for various batteries used around the house. They're
    pretty inexpensive. You can look for them at home improvement stores.

    Patty
     
    Patty, Feb 24, 2007
    #29
  10. smackedass

    JohnO Guest

    We must test the
    While your advice is valid for experienced techs, it is NOT valid for
    those seeking A+ certification.

    Please pay attention to the group you are in, rather than just jumping
    to comment whenever your bot detects someone posting to usenet about
    power or power supplies.

    -John O
     
    JohnO, Feb 24, 2007
    #30
  11. Generally the beep codes of the motherboard will let you know if the
    processor fails.


    --

    The Mön§igñor

    "Sir, I am unaware of any such activity or operation - nor would
    I be disposed to discuss such an operation if it did in
    fact exist, sir."
     
    Mön§igñor ßoddoM, Feb 24, 2007
    #31
  12. smackedass

    smackedass Guest

    Not to sound like a devil's advocate asshole, but, if the motherboard is
    malfunctioning, how do we know that it will beep code properly?

    sa
     
    smackedass, Feb 25, 2007
    #32
  13. smackedass

    w_tom Guest

    Posted was a technique so complex that junior high school students
    do it. A solution that takes 2 minutes using something as complicated
    as an Ipod. Why do you believe this is too complex for A+ Certified
    Techs? Why does John O assume using a meter sold even in K-mart is
    too difficult for A+ Techs?
     
    w_tom, Feb 25, 2007
    #33
  14. smackedass

    smackedass Guest

    But the processor must be attached to the buzzer/beeper whatever it's
    called, attached through the bus, somewhere on the mobo. And if the bus is
    corrupt...right?

    I know, I'm starting to split hairs...

    sa
     
    smackedass, Feb 25, 2007
    #34
  15. smackedass

    JohnO Guest

     
    JohnO, Feb 26, 2007
    #35
  16. smackedass

    JohnO Guest


    Oops, wrong button.

    It's not too difficult, but this skill is not required and it is not
    often taught.

    I have tested over 500 high school and college students on their
    ability to use a multimeter to make basic measurements, in a computer
    repair context. These students come from over 45 different states,
    from hundreds of different tech schools, and the testing has been
    going on for around eight years. That's how I know what they can do.
    Unfortunately for our discussion, I see the advanced students but I
    don't see the average students. Even the advanced students don't have
    much electronics training.

    Then there's CompTIA's Job Task Analysis, a survey of several thousand
    computer technicians and managers of such techs, regarding the tasks
    they perform regularly. This is a huge, industry-wide survey performed
    every few years, and meters didn't make the list. Also, there is
    another bit of CompTIA research called the Critical Incident Analysis.
    This one looks at the most common problems encountered by the entire
    range of computer service organizations around the world, and ranks
    them by frequency. Again, meters don't make the list. This data is
    compelling, unequivocal, and it reflects what the entire computer
    industry does, and what it requires from A+ Certified technicians.
    (note the name of this group...)

    There are very, *very* few middle school electronics programs. Some
    schools teach a couple electronics lessons as part of a wide-ranging
    technology program, but that's about it. Even at the next level up,
    electronics training has been dropped by thousands of high schools.
    Then in computer-repair programs, a growth area, there is a dearth of
    instructors who have any electronics training. Besides that, having
    students probe around inside a live PC isn't something you just let
    any student do. Neither of us would have trouble teaching this skill
    to an average 15 year old, but in a room full of 20 students the rules
    change.

    Finally, the technique you noted is indeed simple enough, and I agree
    it can be useful. However, it would be a mistake to assume that in 15
    minutes every computer tech can understand Ohm's Law well enough to
    analyze a power supply failure. The amount of training required to
    teach this skill (and to use it safely) is quite a bit more than that.
    An electronics training module that gets trainees to that point adds
    4-6 hours to a curriculum, less at higher grade levels. Many schools
    don't have the time, thanks to NCLB.
     
    JohnO, Feb 26, 2007
    #36
  17. smackedass

    w_tom Guest

    If a technician cannot understand Ohms law (I believe I knew it well
    before 12 years old), then what is he doing as a technician? When
    starting in automotive school, what tool are car mechanic students
    provided? The 3.5 digit multimeter. These are auto mechanics. The
    meter is part of their first toolset. Why then are computer repairmen
    too under-educated to use it? I find it shameful that you would
    advocate the dumbing down of America because learning a tool as
    complex as an Ipod is to complex for computer repairmen.

    A multimeter (and no disconnecting) identified the failure or
    verifies power supply 'system' intgrity in but two minutes.
    Shotgunning cannot do that anywhere near as fast nor anywhere near as
    accurately. This is why even auto mechanics have and use the
    multimeter.
     
    w_tom, Feb 26, 2007
    #37
  18. smackedass

    Glenn Guest

    There's one that's named after a president that I might be interested in
    if the price is right.
     
    Glenn, Feb 26, 2007
    #38
  19. smackedass

    JohnO Guest

    LOL, the key term is Job Task Analysis. CompTIA did a huge one. I'd
    share the report with you, but it's copyrighted. The PC service
    industry says entry-level techs don't need this skill. It's that
    simple.

    If you had read my earlier posts carefully, you'd see that I would
    prefer that electronics is included, but *I* cannot make it happen.

    Maybe so, but remember a few messages baack where someone noted that
    Dell always sends a PS AND a mobo? Think about it.

    -John O
     
    JohnO, Feb 26, 2007
    #39
  20. smackedass

    Mister Guest

    About six months ago I think we were warned about w_tom to just ignore
    him. I think the person mentioned he is a know it all of nothing and
    proves it time after time by typing the same thing over and over
    again. If I remeber correctly, he is ignored in other groups because
    of this.
    If w_tom was using a multimeter at age 12, it's ashame he didn't clip
    the alligator clips to his nipples and plug the other ends of the
    wires into the 120 outlet. Then he could really get a grip on what
    ripple is all about as his eyes bounce up and down.
    Or maybe stick the probes in your ears to hear the ripple.

    He will answer you question correctly because he is looking it up to
    make sure he gets it right.

    Enough on w_tom, he probably went through a box of tissues just
    reading how many times his name was mentioned.
     
    Mister, Feb 27, 2007
    #40
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