What is the 'paperclip' method of testing a PSU?

Sirwalrus

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Feb 27, 2013
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I've seen people talking about it, I'm assuming it's a way of seeing if it works without having any other components connected.

Also: This is, more than likely, an immensely stupid question, But, I've heard some people say it's bad to flip the switch on your PSU if it isn't plugged in...

I can't imagine it is, but I'd seen someone say that, and had a friend ask me, so i wsa wondering if there's anything to back that up.

 

Flying-Q

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Even modern, well protected PSUs need some load on the end of them when you turn them on even if it is as little as a fan.

The paperclip method involves connecting the standby line (pin 16, green wire) to a ground line (pin 17, black) to signal to the PSU to turn on, just like the motherboard does when you press the power button on the front of the machine. Unfortunately all this tells you is that the PSU turns on. In this condition you can get a voltmeter and measure the outputs, but as there is no live load that doesn't tell you much.

The only way of properly testing a PSU is with a testing rig that measures all aspects of the supply under load conditions. That is electrics and electronics of a sophisticated nature.
 
G

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It's exactly that, simply shorting out the two connectors that are responsible for powering the unit on/off. So that you can test and see if the power supply itself is good or bad, while ruling out the possibility of other bad hardware.
 

Flying-Q

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Feb 20, 2006
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Even modern, well protected PSUs need some load on the end of them when you turn them on even if it is as little as a fan.

The paperclip method involves connecting the standby line (pin 16, green wire) to a ground line (pin 17, black) to signal to the PSU to turn on, just like the motherboard does when you press the power button on the front of the machine. Unfortunately all this tells you is that the PSU turns on. In this condition you can get a voltmeter and measure the outputs, but as there is no live load that doesn't tell you much.

The only way of properly testing a PSU is with a testing rig that measures all aspects of the supply under load conditions. That is electrics and electronics of a sophisticated nature.
 

Sirwalrus

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Feb 27, 2013
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Thanks, that's what I assumed. Any ideas about my other question? (Will it damage the PSU if you flip the power switch on it on without it being connected to anything?)
My freind is building a PC to and he asks me that question every d**n night and I can't find anything.
 

Flying-Q

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Any PSU that is turned on needs to supply current to something. If it does not then there is wasted energy in the tranforming process that gets fed back into the guts of it. It will heat up. Now, top of the range PSUs have protection circuitry that will prevent any damage from this excess heat by shutting the PSU down or other appropriate measures.

Older or lower grade PSUs are unlikely to have this level of protection so they must be connected to some kind of load for transmission power-balancing to reduce that overheating. That load can be as little as a normal 12volt fan. Any kind of lower grade PSU can be killed very effectively by having it on with no load. Let your friend switch it on as a learning experience. The wallet is usually a good teacher.
 

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