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Thread: Paper Clip Test

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  1. Member wulf109's Avatar
    Join Date: Jul 2002
    Location: United States
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    I was setting up a computer and it shutdown. Guessing I had a bad power supply I did the paper clip test and the fan didn't spinup. I tried the test on another power supply and it spunup. That PS isn't suitable for the computer I was setting up,so I ordered a new PS. Is the paper clip test reliable?
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  2. Member
    Join Date: Mar 2008
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    What paper clip test? Is it reliable for what?

    If you're talking about shorting some of the pins on the connector block,
    aren't you only bypassing the power switch on the front of the case?
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  3. Member
    Join Date: Oct 2004
    Location: Freedonia
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    Originally Posted by davexnet View Post
    What paper clip test? Is it reliable for what?
    I agree. What the hell is this "paper clip test"?

    Is it reliable? If people here as asking "What the hell is it?" then I think your answer is "No".
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  4. Member
    Join Date: Jan 2007
    Location: Republic of Texas
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    The paper clip test does work, provided one end is securely in the green wire slot on the 20-pin plug, and the other end is in a black wire slot to either side of the green wire slot. I did a variation of this when adapting a 550 watt ATX power supply for a DVD duplication tower (which, of course, did not use a PC motherboard). My own modification connected the tower case power switch to the green and black wire slots on the 20-pin plug, but pieces of paper clips were used to turn female connections to male.

    For those of you who are baffled by what the hell we are discussing, do a google search on using a power supply without a motherboard.

    With all that said, it sounds like you have a bad power supply to begin with.
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  5. Member turk690's Avatar
    Join Date: Jul 2003
    Location: ON, Canada
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    Originally Posted by jman98 View Post
    What the hell is this "paper clip test"?
    On a standard PC power supply, it involves disconnecting the 24-pin ATX connector from the main board, identifying the PWR ON wire (usually green, though PSUs of some branded PCs like HP, Dell, etc. may use their own different color coding) and any GND wire (black), then shorting them together with a paper clip bent into a "U". Since these two pins are side by side on the connector, shorting them together is not a complex thing to do.
    But all this test proves is that the standby voltage is present (+5Vdc, purple wire) and the power-up circuitry is ok. At the very least the PSU fan will start to rotate, which may imply the +12Vdc rail (or one of the +12Vdc rails, if there are more than one) is good. Nothing about other potential problems can be inferred. Like, defective electrolytic caps, mostly on the +3.3V, +5V, and +12V rails can shut down the PSU when the CPU and GPU start drawing serious current after the initial power-on. Or, dust bunnies not immediately obvious from the outside make the PSU overheat when it starts drawing heavier current after booting and shut it down.
    Different PSUs can also have different behaviours which may make the paper clip test not work, or work unreliably. To turn the PSU on, the POWER ON line is held low (to ground, which is done by a latching circuit that is controlled by an SPST switch on the PC front panel; this is the PC power on/standby switch). After a predetermined period (of a few milliseconds) the POWER GOOD (PG) wire should have detected the correct voltages are present and allow this latch to exist in the current state (low), letting PSU continue outputting power. If the connector is pulled out, the PG state is undetermined (high Z) so may shut the PSU down.
    Tablet? No, I don't have a tablet. I have a life.
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  6. The test for a suspected bad power supply is to replace it with one that you know works. Anything else is guesswork and wasted effort. PSU's are a high-failure-rate item, if there is a reason to suspect it is bad, it most likely is.

    Knowing that it has life and will spin the fan does not tell you what you want to know, which is "will it fire up the motherboard?"

    If you really just want to short something, eliminate the case switch and short the pins for power-on directly on the mobo.
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