Editing ATX (section)

==== Power connection to the motherboard ====
The power supply's connection to the motherboard was changed from the older AT and LPX standards; AT and LPX had two similar connectors that could be accidentally interchanged by forcing the different keyed connectors into place, usually causing short-circuits and irreversible damage to the motherboard (the rule of thumb for safe operation was to connect the side-by-side connectors with the black wires together). ATX uses one large, keyed connector which can not be connected incorrectly. The new connector also provides a 3.3&nbsp;volt source, removing the need for motherboards to derive this voltage from the 5&nbsp;V rail. Some motherboards, particularly those manufactured after the introduction of ATX but whilst LPX equipment was still in use, support both LPX and ATX PSUs.<ref>{{cite web |url=http://www.createch.com.tw/images/Backplane/cbp-14p7-2.jpg |archive-url=https://web.archive.org/web/20131213101935/http://www.createch.com.tw/images/Backplane/cbp-14p7-2.jpg |url-status=dead |archive-date=13 December 2013 |title=Example of a motherboard that can support connecting AT and ATX PSUs |publisher=Createch.com |access-date=18 November 2014}}</ref>

If using an ATX PSU for purposes other than powering an ATX motherboard, power can be fully turned on (it is always partly on to operate "wake-up" devices) by shorting the "power-on" pin on the ATX connector (pin 16, green wire) to a black wire (ground), which is what the power button on an ATX system does. A minimum load on one or more voltages may be required (varies by model and vendor); the standard does not specify operation without a minimum load and a conforming PSU may shut down, output incorrect voltages, or otherwise malfunction, but will not be hazardous or damaged.<ref>{{cite web |title=PC Power Supply Requirements and Troubleshooting Problems |url=https://reprap.org/wiki/PC_Power_Supply |publisher=[[RepRap project]] |archive-url=https://web.archive.org/web/20180919080407/https://reprap.org/wiki/PC_Power_Supply |archive-date=September 19, 2018 |date=September 19, 2018 |url-status=live}}</ref> An ATX power supply is not a replacement for a current-limited bench laboratory DC power supply; instead it is better described as a bulk DC [[power supply]].<ref>J. B. Calvert. [https://web.archive.org/web/20171101033821/https://mysite.du.edu/~etuttle/electron/elect62.htm "Using a Computer PSU"]; University of Denver.</ref>