Introduction: Convert a PSU Into a Bench Power Supply
You see, I've been building projects since I was 12. And now that I'm a little bit older and wiser I've come to notice that battery powered supplies are a hassle and wall wart single voltage series just don't work when powering certain projects. So from a couple of hours of research I have created a DIY bench power supply from a scrapped computer power supply. Please read to the end before beginning this project.
I AM NOT RESPONSIBLE FOR ANY INJURIES CAUSED BY BUILDING THIS PROJECT!!! YOU WILL BE WORKING WITH 120 VOLTS A/C!
ALWAYS LET YOU POWER SUPPLY SIT FOR A DAY, WEAR ELECTRICITY RESISTANT GLOVES OR PUT A RESISTOR INBETWEEN THE 5 VOLT AND GROUND PINS!
Step 1: !!!PARTS!!!
So as many of you know, you are gonna need a couple of things to build something like what I have.
1 - 300 watt or higher computer power supply
1 - on off on switch
2 - on off switches
1 - 2 live 2 ground speaker terminal
6 - red banana plug
3 - black bananas plug
1 - cigarette lighter socket
1 - breadboard
1 - 10 watt 10 ohm resistor
1 - small 2 pin fan
Assorted terminal connectors
Lead free solder
Heat shrink tubing
Solder fume extractor
Assorted ring terminals
Screwdriver that works with the screws
Needle nose pliers
That is the full list for the electronics part. I will not cover anything past creating the electronic circuit. You will need to build your own box. There are two pictures of blue crimp able terminals above both are blue. The first will be referred to as the other and the second referred to as a ring terminal .
Step 2: Stripping Down to the Bare Basics
First thing is first. Grab out your power supply. I do not have pictures for this step. Make sure that the psu has been disconnected for 3+ days or grab that resistor and put it between a 5 volt and a ground pin. Cut off all of the connectors coming out of the PSU nearest to the connector. Next, the PSU case comes into two pieces, pull the top from the bottom and it should reveal a box about the size of the case, next grab some snips and cut all of the wires connecting the psu to the 120 volt connector. Leave enough length in both ends of the wire. Save that part for later. Next snip off the power switch and throw out the switch or keep it. We don't need it. Now take the board out of the case. Also grab the fan and take the 120 - 220 volt switch out.
Step 3: Tinning and Thinning
So you have a psu. Now grab the snips, heat shrink and lighter. Read the chart above. You will need 4 5 volt wires, 1 3.3 volt wire, 2 12 volt wires, and all of the ground wires. You will also need the green wire and any wire that is a voltage regulator wire. Every other wire can be snipped and heat shrinked. Grab out some ring terminals, wire, crimpers, iron, solder and strippers. Strip and Tin all of the remaining wires and then put ring terminals on 3 red wires and put 9 black wires into 3 yellow ring terminals. Take one red wire and one black wee and put a 10w 10ohm resistor between them. Also put one of the other terminals on the green wire and another on a black wire. After you have done that put the second type of terminal we have on the rest of the wires. Heat shrink any remaining black wires
Step 4: Extenders and Contenders
Now we have to make some wire jumpers. Take out some red wire, strippers, crimpers, iron and snips. Cut 4 pieces of red wire. 2 medium length and 2 long. Strip all of the ends and tin them. Now take all of the short pieces and put ring terminals on them. For the long pieces put a ring terminal on one side and that other type on the opposite side. These wires will be used only if you are building with the exact same wiring job as me.
Step 5: Connections and Circuits
On to step 5. So you have done all of the previous steps huh? Well now I will explain the wiring.
3 5 volt wires to 3 red banana jacks (jacks)
3 sets of ground wires to 3 black jacks
1 ground wire to on off switch #1
1 12 volt wire to on off on switch
1 12 volt wire to on off switch #2
1 3 volt wire to on off on switch
2 red wires to 5 volt jacks
2 black wires to ground jacks
12 volt socket:
Red wire to on off switch #2
Black wire to ground jack
On off on:
1 12 volt wire in
1 3 volt wire in
1 red wire to three banana plugs using 1 long extender and 2 medium ones.
On off #1:
Green wire in
Ground wire out
On off #2:
12 volt wire in
12 volt socket red wire out
Step 6: THE HOME STRETCH!
Now, assuming that you have made your box and put everything inside it, you can test all of your connections and plug in a fan. Make sure to re solder the power terminal on to the board. take pictures and post them in the comments. If you need to trouble shoot post in comments and I'll help you out.
ALL FEEDBACK IS APPRECIATED. But be nice please, I'm only 14 and this is my first instruct able.