Help with power supply "paper clip" test

[marciotf]

Hi,
I have a simple doubt, I am currently testing my power supply since my computer wont turn on. I took the power supply off the case, connected only a fan to the power supply cabling, and did the paper clip thing.

When I turn the power supply on, I can see the power supply internal fan spinning all time. But the external fan connected to the power supply only spins for like 1,5 sec when I turn the power supply on, then stops.

Should the external fan be spinning all the time, or only for a sec when I push the on button?

PSU is an Enermax Coolergiant EG701AX-VH.

Thks,
Marcio

 

[General Kenobi]

Well, it stands to reason that if you're connecting a fan to the PSU via a molex connector, it should be running continuously when the power is turned on.

I'm not familiar with the "paper clip test" though.

 

[jonnyGURU]

Well, it stands to reason that if you're connecting a fan to the PSU via a molex connector, it should be running continuously when the power is turned on.

It does not stand to reason. An ATX power supply is not on simply because it's plugged in, the switch on the rear is in the on position and has a load on it.

ATX power supplies need to be "told" to turn on with a short of the power on signal lead. That's where the paper clip trick comes in. If you use a paper clip to short the +5V signal on the green wire to one of the black ground wires, the power supply should be on.

As for the OP's problem: You should test those leads with a multimeter. It could very well be that the fan doesn't provide enough of a load to keep the rail within spec. Especially if it's an old school CoolerGiant. Hook a hard drive up so there's a load on the +5V and +12V and try again, but I'd still like to see you use a multimeter as well.