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Computer power supply tester; buy which one?

Discussion in 'Electronic Repair' started by Whamspam, Mar 19, 2007.

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  1. Whamspam

    Whamspam Guest

    No problem with my computer. I just want to play.

    Power Judge by PowMax:


    CoolMax Power Supply tester:


    I can't find any instructions on the internet for using these things

    I was thinking about hooking one of these to an empty power socket with
    everything else hooked up. Should be able to boot up and diddle with my
    computer without any error signals popping up. Does that sound like a

    Lingering questions regarding quick pulses or dips in voltage, how high
    or low or wide, whether these test devices will recognize quick
    excursions outside the voltage limits and hold the error display...?

    Maybe I'm getting too deep. If my [slow] DMM is happy, then should I be

  2. Jeroni Paul

    Jeroni Paul Guest

    There is much more to test from a power supply than just its
    electrical behaviour. It can have bad solder joints, weak capacitors
    or intermittents, causing hangs only at long term. At full load may
    fail to regulate properly or hold at all. Only long term usage in the
    target system will tell if it works properly. Marginal supplies may
    work better in some systems than others.
  3. James Sweet

    James Sweet Guest

    They're all pretty worthless, just buy a multimeter. You can poke the
    probes in the back of the ATX connector while the computer is running.
  4. JW

    JW Guest

  5. Really? A power supply tester is handy if you have to go through a
    lot of power supplies. I have two other models that see a lot of use.
    In fact, I used one a few days ago to show someone that their supply was
    bad. Its true that a cheap tester won't find EVERY problem, that do
    kick out a lot of the bad supplies faster than a voltmeter and jumper.
    it also eliminates the motherboard's power control circuit and front
    panel switch. i have seen plenty of bad switches, and a number of bad
    motherboards that wouldn't turn the PS on.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida

  6. You disconnect the 20 or 24 pin cable from the PS at the motherboard
    and connect it to the tester. It puts a load on the +5V supply, and
    allows you to meter the voltages. I have never seen one made to be used
    along with the motherboard.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  7. James Sweet

    James Sweet Guest

    If you have 100 psus and need to do a quick check on them the tester
    could have some value, but for what the OP requested, the tester will be
    next to worthless. If you want to evaluate the condition of just one
    or two psus, you have to do much more extensive testing.

  8. James, I built test fixtures at the Microdyne factory to test power
    supplies for their $20,000 to $80,000 telemetry receivers. We did a lot
    of tests to EVERY one of the $700+ power supplies before they ever got
    close to a radio. You have to know your test equipment, and when to use
    what. Denying yourself some simple tools for quick tests is a stupid as
    trying to work with no test equipment.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  9. w_tom

    w_tom Guest

    Which is exactly why one buys the multimeter and does not use a
    'magic box' power supply tester. The former provided a definitive
    answer and with numbers that can obtain further useful information.
    The latter (power supply tester) hardly applies a load, does not
    really say why it is 'go or nogo', and never really provides a
    definitive answer. Get the meter because one needs simple tools for
    quick and reliable tests. A tool that is also useful for solving
    other electrical problems - not just the power supply.

    Power supply tester will not even provide a definitive answer AND
    makes useful assistance from others almost impossible (no numbers).

  10. Yawn. Go troll somewhere else.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  11. w_tom

    w_tom Guest

    Michael must denigrate when he cannot technically justify what he
    posts. Michael was a technician who wired boxes without knowing what
    those boxes did. An informed lurker uses a meter as recommended by
    many others; ignores a technician who must attack the messenger.
    Why? He cannot technically defend his recommendation.
  12. hmmmmmmm a MULTIMETER is gonna apply even LESS of a load than a power
    supply tester.
    basically computer power supplys work or they dont , all he . me want to
    do is see if they work or not.

    why wont the power supply tester work ?
  13. multimeters put less load on than the computer power supply testers.

  14. a MULTIMETER puts a LOT LESS LLOAD on than a power supply tester.
    a multimeter will show the same results as the tester , wether there is
    the corrct voltage or not....simple.
  15. DaveM

    DaveM Guest

    No.. it's not that simple. A PS tester puts a minimum load on the main
    regulated output of the PSU; just enough to allow the PSU to come up. All the
    other outputs are totally unloaded. The tester only provides an "idiot light"
    indication of the condition of the PSU, whereas a digital multimeter, even a
    cheap one, will provide a qualitative indication of each of the PSU outputs...
    and under actual loaded conditions (if the PSU is left connected in the PC).
    With those measurements, you can make a much better determination of the
    condition of the PSU. Who knows the voltage limits of the LED indicators on the
    tester? Nobody specs that for their testers, at least for none of the testers
    that I have seen on the net.
    With a multimeter, you will know, with known accuracy (within the spec'ed
    accuracy of the DMM), what the actual output voltages are. The tester won't
    give you that info.
    True, the DMM still doesn't give you the total picture, such as ripple and noise
    on the outputs, but knowing the actual voltages on the outputs is an order of
    magnitude better than what the "idiot lights" tell you.
    Yes, it takes a bit more time to check each output individually with a DMM, but
    it's a much better test. On second thought, it might even take less time to
    check with a DMM, because you don't have to disconnect the PSU from the
    motherboard, then hook up the tester, then turn on the PSU. With a DMM, you
    only have to gain access to the PSU connector and touch the probes

    As far as testing a pile of PSUs, I guess you can use a tester to cull out the
    obviously dead ones rather quickly, but beyond that, I question its value.

    Dave M
    MasonDG44 at comcast dot net (Just substitute the appropriate characters in the

    Life is like a roll of toilet paper; the closer to the end, the faster it goes.

  16. And?

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  17. w_tom

    w_tom Guest

    Please read the procedure before posting. Standard procedure: never
    disconnect and never remove anything until AFTER data is collected.
    Disconnecting a power supply or using the power supply tester; both
    are testing with virtually zero load - not informative and not
    useful. And both do disconnecting. Meter in but two minutes does
    best test because nothing is changed or removed. Best load is
    motherboard and active peripherals. Best data is numbers; not a GO/
    NOGO light. No numbers and no load from a power supply tester reports
    little that is useful and provides no useful (and further) information
    from newsgroups.

    See DaveM post for further information. Get the meter to save time,
    accurately repair the first time, and become informed as to why things
    fail. Shotgunning or that power supply tester reports so little and
    teaches nothing.
  18. James Sweet

    James Sweet Guest

    Yes, that's what the rest of the computer is for. As I said, poke the
    probes into the *back* of the connector pins while the PSU is powering
    the motherboard.
  19. James Sweet

    James Sweet Guest

    No they don't "just work or they don't". All kinds of things can go
    wrong with power supplies. Output voltage can be too low or too high or
    sag under load, there can be excess ripple, glitches, plenty of faults
    only show up when heavily loaded. I just replaced an Antec power supply
    recently that powered up fine and all voltages checked out ok, but the
    outputs would gradually sag under load until the computer would just
    randomly shut off. A PSU tester would have passed that one with flying
    colors but it failed in service and using a multimeter while it was
    operating the computer in question was the only way to diagnose it.

  20. Yawn. Give it up Tommy boy. You have to spread lies about anyone
    you disagree with. Why don't you just go back to and leave these good people alone? You never contribute anything
    useful. You only copy & paste your views on surge protection, while
    citing quotes from agencies that are long gone.

    No matter what you say about me, makes no matter because you are
    simply an anal retentive usenet kook and and love to start flame wars.
    Tell me, do you have Google groups email you every time your name, or
    surge protection is mentioned? The engineers on
    have repeatedly driven your spew into the
    ground, and all you can do to counter it is to copy & paste the same old

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
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