how to hotwire an ATX power supply ( and why you would want to)

[pierhogunn]

I have come by the following pieces of technology

2 squirell-cage blowes from a IBM Blade-Center enclosure... these thing consume 12V 10A and 120W of power, and sound like a jet engine taking off, massive airflow

1 550W ATX power supply

the thought is that I will hotwire the atx power supply so that it will drive these two fans that I am going to build into an enclosure that I hang from the ceiling and just have fun with.

so how do I hot-wire this ATX power supply?

[Tequila]

Check google for "test ATX power supply" and you should find the answer - you just need to jumper a couple of pins with a resistor to simulate a load.

I'm not sure if the PS will be able to handle the 10A output though. If i remember right, each 12V channel on the ATX is usually only good for around 5.5A max.

[crokett]

Those blowers do move a ton of air. And yes they do sound like an airplane. How'd you get em?

Here is a link to hotwiring a power supply. http://www.instructables.com/id/Conv...gular-DC-Powe/

As I recall in the lab we jumpered the green??? wire at the plug to ground to fool it into thinking it is always on.

[LCHIEN]

Check google for "test ATX power supply" and you should find the answer - you just need to jumper a couple of pins with a resistor to simulate a load.

I'm not sure if the PS will be able to handle the 10A output though. If i remember right, each 12V channel on the ATX is usually only good for around 5.5A max.

In addition to the load rating on the 12V possibly being inadequate, the switching power supplies for most PC's are very sensitive to minimum load on the logic power supplies... the supply simply won't start if there is not an appropriate 3.3 or 5V load.

A typical load on the logic supplies is probably around 200-250 watts, but I don't know what the minimum load is, probably varies from maker to maker.

[pierhogunn]

I plucked them out of the decommed IBM blade chassis that we are sending to Ohio for scrap, I just wish I knew what the pin-out on the stinking thing was,

Joe/Loring, the PS is rated for 18A load on the 12V leg of the supply I don't necessarily need to use the molex connected legs, but I was thinking about using the part that plugs into the MB

[pelligrini]

I've used a paperclip to hard wire one on. Just ground the green one, PS-ON. Green to black or to the PS casing. Pinout from Google