In order to keep the Williams Defender harness I have as original as possible, I don’t want to replace any of the original connectors so instead we are going to make the linear PSU and the original Williams PSU totally switchable using connectors.

1. Acquire male and female ATX connectors

The number of wires used, and the voltages represented by standard PC ATX connectors are fairly similar to the amount of wires on the Williams Defender standard harness so they provide a good way of making the original Williams PSU connector and our new linear PSU connector interchangeable.

Maplin ATX connectors

2. Hold our breath and snip the wires for the original Williams PSU connector

photo 2

3. Crimp all of the wires with our new ATX pins

New ATX crimp pins in place (boring...)

4. Complete our ATX -> Williams PSU connector for 100% compatibility with original Williams PSU

Williams to ATX interface

5. Wire in our Switchable PSU to the other ATX connector and connect up

ATX connected up to Linear PSU

6. Wire up the +5V, +12V and -5V to the linear PSU

Wired up Linear PSU

photo 4

7. Sit back with a cup of tea and admire our handy work (you can see the original Williams PSU connector wired as well in the top of the photo)

Williams PSU to ATX