ATX Pinout

ATX Power Connector


Atx pinout.GIF

Please note that this connector's pins are numbered oddly - not in the normal manner Instead it is numbered like the odd-ball Sub-d connector. Probably someone who had not laid out many PCBs did this. (A normal approach would have been to number it counterclockwise looking at the sockets or clockwise looking at the pins)

Pin Signal Wire Color
1 +3.3Vdc Orange
2 +3.3Vdc Orange
3 GND Black
4 +5Vdc Red
5 GND Black
6 +5Vdc Red
7 GND Black
8 PWR-OK Gray
9 +5Vdc
standby Voltage
10 +12Vdc Yellow
11 +3.3Vdc Orange
{brown is 3.3Vdc
12 -12Vdc Blue
13 GND Black
14 PS-ON Green
15 GND Black
16 GND Black
17 GND Black
18 -5Vdc White
19 +5Vdc Red
20 +5Vdc Red

Testing ATX power supplies

Cheap power supplies are the source of many intermittent computer failures. Recommended computer components. There are some passive testers but they really don't do a good job of testing. You would want to both use a passive load and a real computer load and look at the noise on the signals with an oscilloscope.

To test the basic function of an ATX power supply, short the Green wire with one of the grounds. This should turn the power supply on.

Issues with Dell

Please read how Dell ATX pinouts are different and if not used properly can destroy your motherboard!

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This information may have errors; It is not permissible to be read by anyone who has ever met a lawyer.
Use is confined to Engineers with more than 370 course hours of electronic engineering for theoretical studies.
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