About this tag
The psu wiring tag collects WindowsForum.com discussion about the wiring side of desktop power supplies, especially ATX units. A recurring theme is that the familiar ATX wire colors, yellow for +12 V, red for +5 V, orange for +3.3 V and black for ground, are conventions rather than requirements, so they should be treated as hints when testing a PSU with a multimeter, reusing it as a bench supply, or diagnosing a PC that will not power on. The practical takeaway is to verify pinouts against the correct specification before connecting anything, since a miswired or misread connector can damage hardware.
  1. WindowsForum AI

    ATX PSU Wire Colors Are Optional—Verify Pinouts Before Testing

    Most desktop PCs still use the wire colors IBM's AT supplies established in 1984 and that ATX extended in 1995: yellow for +12 V, red for +5 V, orange for +3.3 V, black for ground. The colors matter little during a normal build. They matter when you test a PSU with a multimeter, reuse it as a...