A Sleak Bench Power Supply From PC PSU





Introduction: A Sleak Bench Power Supply From PC PSU

About: Designer, Maker, CNC Enthusiast, Drone Maker

Update: The reason I have not had to use a resistor to stop the PSU auto powering off is that (it think...) the led in the switch I used draws enough current to prevent the PSU shutting down.

So I needed a bench top power supply and decided to make another PC power supply conversion tutorial. I used my CNC though, so this is less of a tutorial and more of a build log.

I uploaded this here in the hope that anyone making one for themselves can perhaps take inspiration for there own build.

please do check out my blog for other projects: http://livealittlemore.co.uk

Step 1: Design

I designed the parts in Illustrator and saved them in SVG fromat so my CAM program can process them for my CNC machine (see video for machining)

Step 2: ​You Will Need

You will need:

1. a PSU (ATX size) from a computer that has about 300w of power (depending on what you are going to use it for) 2. binding posts (here is a UK link for where to get THEM)

3. A latching switch of some kind (I used one with an led ring around it built in)

4. a piece of low density foam (fan filter)

5. some wood glue

6. 10mm plywood for the frame... PLANS

7. 3 M3 screws/bolts with washers.

8. a CNC machine...you probably won't have this...sorry!

Step 3: Cutting and Gluing

Watch my video to see my machine cutting out the pieces, you could do the rabbit joints by hand but it would be tricky in plywood!

Glue it all up and clamp it in place.

Step 4: Sand Down, Varnish Front Panel and Paint the Rest of the Box

Sand down with some fine sand paper to remove any burs and get edges perfectly smooth if not already.

I used varnish on the front panel for aesthetics as I like the wooden front with a matt black back to the box.

Step 5: Add Binding Posts

These binding posts were nice and cheap and do the job nicely. they have a bolt that pokes throught the front pannel and a little tab like washer which you can solder to on the other side. Secured in place with a nut.

Step 6: Assemble and Wiring

I then put the power supply in the housing and bolted it into place. I then soldered everything up. {I used two wires per voltage to increase the current output at each voltage if i needed to power a heavy duty motor or something. The switch I used had a built in led ring around the button which can be connected up to 5v and will illuminate when the power supply is turned on.

On the subject of the switch, i messed up the hole for it as you can see in the pictures, so I machined a little wooden washer which I stained a dark oak colour for contrast.

Step 7: Fan Filter

I made a fan filter for the intake of the psu to stop too much dust getting in. the exhaust is where the power chord goes in by the way.

Step 8: Add Labels

And that is pretty much it, add some labels so you know which posts correspond to which voltage and you are done!

please do check out my blog for other projects: http://livealittlemore.co.uk



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23 Discussions


2 years ago

nyone can help I don't something similar to this, I have a USB type a port wired to a 5v supply, when an iPhone charger is plugged in it trips my psu, is this because of the current the iPhone charger tries to draw? As I now have noticed type a USB is only upto 0.5A

What about to some trick that I read some time ago about to put some resistance between pins (Does you know wich ones?) to make the PSU to think that is plugged?

Anyway... tks for the post... I need one of those...

4 replies

Update: The reason I have not had to use a resistor to stop the PSU auto powering off is that (it think...) the led in the switch I used draws enough current to prevent the PSU shutting down.

Hello, I hope it's not too late but I know what are you talking about. First you have to short PS ON and GND pins (green one, and a black one). That is for PSU to even be able to power on. I have been thinking to put switch in that connection since my PSU does not have a back switch. Anyways, secondly you should go get one low resistance but high power resistor, I am using 10ohm 10watts and plug it in between 5V (red cables) and ground (black GND). Be very careful with that and ensure good connection because that resistor WILL get VERY hot. Thats pretty much it. Enjoy

I think I know which trick you are referring to, the way I learned it is that you take a paperclip and bend it so that it has two prongs, then you put one in a ground pin and the other on the green pin and that usually tricks the PSU into thinking that it is plugged into a power source. I learned and used this trick for testing power supplies although it isn't the safest or most accurate way, it certainly did the trick.

This might help you somewhat.


I made one very similar to yours but I used the existing case, added the pins, a blue LED & a rotating speed adjustment switch and the resistor method. I use mine to power my car windscreen wiper spit motor. If you look in Google you will find detailed instructions. I had lost the link I used now sorry. It works great. Never fails.

Perhaps I missed it, but did you allow for the back or a side to be removed for cleaning or adding components, eg, fuses?

5 replies

Thank you! I missed that.

You did a great job with the design and with the Instructable.

5 thumbs up!

yeh the power supply I used has a short protection circuit so anyhting over about 15 amps on the output will make it turn itself off!

That looks really good. I made one last year, but I just reused the PSU case and mounted my switch and jacks to the cover. Your effort really shows, though, a much more appealing unit.