# Computer P/S To Test Head Unit



## Captain Paintball (Mar 18, 2007)

I wanted to test some old car stereo decks with an extra (computer) power supply I had sitting around. I plugged it in, hooked it up, and...nothing. 

(now here is the part where I speculate) 

Then I realized there is a 4 pin connector that connects to the motherboard that, for the ease of explanation, I will call a 'trigger" switch. I 'believe' when the power button is pressed, the signal goes to the board, then through this trigger to the power supply, and turns on the fan/provides power to the rest of the system. 

1. Is my observation even correct? 

2. Would cutting off that molex 4 pin connector and adding a toggle switch make this P/S work correctly? I'm drawing a blank here, but I don't that that'll work... 

3. MAIN QUESTION: How would I go about making this P/S work for car stereo applications?


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## smokinkane (May 17, 2007)

If your using an ATX power supply the green wire in the ATX plug can be shorted with any one of the black ground wires to power cycle the power supply. That is what the power button on the computer does, it shorts the green wire. You can get your 12v out of one of the molex connectors or directly out of the ATX connector on the yellow wirel (pin 10). Just use one of the black cables for ground, hope this helps


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## Captain Paintball (Mar 18, 2007)

I knew, logically, that the power button didn't shoot a quick shot of power to the mother board...it was just a button! I didn't think about shorting, though. But thanks to you, I am clear. Thanks! I will try it out later tonight or tomorrow.


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## Xander (Mar 20, 2007)

Yeah, and note that you also don't have to keep the wire shorted, just until it turns on, then you can disconnect it.

My friend just helped me build my computer, and we didn't have a switch (I modified a case, so no power switch on it), so we put a huge toggle switch on it. so to turn on computer I flip it up and down real quick, it's awesome.

time to turn on the computer...kerchunk, kerchunk


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