Overview

Modern ATX power supplies do not have -5V. But some retro PCs require -5V. This can be the case for the motherboard itself or especially for some add-on cards, such as certain Sound Blaster sound cards. If the motherboard requires -5V, it may not boot, or it may function incorrectly. And since modern ATX power supplies do not provide -5V, this can be a problem.

What this adapter does is add the missing -5V back to the ATX: adapter board plugs into the motherboard, and either 20 pin or a 24 pin ATX power supply then plugs into the adapter board. The adapter board will then inject the -5V back to the output side, and into the correct pin on the motherboard ATX connector.

Note that you do not need this adapter unless you know you need the -5V. More modern sound cards for example do not need -5V.

Modern power supplies also have more advanced features such as over current and over voltage protection, so you may want to use such, even if you have an ATX power supply with -5V. Those old power supplies are aging and could fail catastrophically.

Make sure that none of the electrical connections short to any surrounding components or things like the CPU heatsink. Also make sure that the input connector is firmly pushed into the adapter, and that the adapter is firmly pushed into the motherboard socket, and locked in with the clip. This way the adapter will stay rigidly in its place.