Building a Modular PSU

Wiring it up

With the new jacks in place, you can screw the PSU's circuit board back in. Now, it's time to trim some ugly wires! You can cut in any order you would like, but it's recommended that you attach them with the longest wires (the farthest molex) first to make sure your routing is clean inside the PSU.


Once we're done hacking and before we start soldering, let's clean up our mess, shall we? The cables that you snipped from that PSU are still needed, as they'll be our new modular cables (hey, they're already cut!). Start by throwing on some sleeving, then attach the male 25-pin connector.

It's EXTREMELY IMPORTANT you make a note of what pin goes to what wire colour and even the wire thickness if there is more than one colour. For example there will be more than one red and black cable on the ATX connector and it's highly likely that some are thicker than others - this is important and you should make a note so as to match your new modular cable to the modular connector on the PSU itself. Connect it wrongly and at best your PC won't boot, whereas at worst you will have a new and expensive brick.


Next up are the four-pin molex connectors. After trimming the old cables off, solder the PSU cables to the microphone jacks. Remember to keep the order of your cables the same! It easiest to work from the farthest back towards the ATX connector. This leaves you plenty of room to connect the ATX connector, which is much trickier work!

When soldering - remember to invest in some good flux as it will not only make the job far easier, but it will make the join neater. These connectors are quite close together and you don't want excess solder creating a short. Heatshrink is also very useful here as it isolates every connector.


With the molex connectors made, it's time to sleeve up the cables. Once they're sleeved, attach the other end of the microphone jacks to each pair. Remember, again, to match up the colours of the cables correctly!

Now that everything else is out of the way, it's time to wire up that ATX connector on the PSU side with the same techniques and advise we gave above.