DIY Lab Bench PSU
My old Bench PSU had died and I needed a new one for my water-gun project (Work in progress), so it was a good time to document the process as well for the benefit of others.
List of materials.
- A discarded computer Power Supply Unit. (PSU)
- At least 2 terminals
- 2-state flip switches
- A 12v fan
- an on-off rocker switch
- LCD Voltage meter (Optional)
- Sandpaper & Paint (Optional)
My Donor PSU has a large 120mm fan on top of it that is not very useful. It takes up all the space. It had to go. As a replacement I used the top off another PSU with no top fan. The dimensions are the same anyway.
First step is to open it up as see what we got.
Some dust bunnies, and a lot of dirt. I vacuumed it and then cleaned it carefully with an old toothbrush. Bellow you can also see the 110v-220v switch. I never plan to use it on 110v so I removed it.
Next step is to figure out the layout of all the switches, fans, etc. I drew the outlines as a guide for the dremel.
I used the carbon fiber bit for the straight cuts and the metal drill bits for the holes. It took me hours to finish it.
I then sanded it and gave it a bright white finish. I then cut all the excess cable, but left a power molex intact to use it as a PC components tester.
This is the main on-off switch. Cut-off the main motherboard power molex, and connect the green and the black to the switch so that when you flick the switch, the circuit closes and the PSU thinks that the motherboard is on. When soldering, I recommend you use a “handy tool” for holding the cables. It’s very handy.
My new revised design uses just 2 terminals, and 4 flip-switches as voltage selectors. This way when you want to change voltage you don’t have to connect and disconnect to various terminals. You can also see the LCD voltage-meter bellow. I used hot glue to fix everything in place. It doesn’t look very good on the inside, but looks flawless on the outside.
I glued rare-earth neodymium magnets to store the test-molex on the side of the case. This way it’s out of the way and at hand when needed.
Here is the final result. I love the black and white theme. Reminds me of stormtroopers.
For the final touch I added some labels with a sharpie. Available voltages are 3.3V, 5V, 8.3V, 10V, 12V, and 17V.