Building DC Power Supply From ATX Power Supply

If you're like me , you've probably toasted dozens of cheap AC-DC adapters , on my last project , the adapter melted and almost caused a fire when it's wires got shorted out , thats when I realized I need a better DC power supply , decent DC power supplies can get expensive , so I decided to build an ATX power supply , since I had many junk PCs lying around . 

ATX power supplies can give up to 30 Amperes of current , 3.3v , 5v , or 12v voltage , and automatically turns off in case of electric short .  

Parts list :

1. Pentium 4 ATX power supply.
2. Red LED.
3. Green LED.(Optional)
4. Toggle switch .
5. 4 Banana connectors .
6. 2 100k resistors.
7. 2 Flat Push-on connectors.(Optional)

Tools list :

1. Metal drill bits 5mm for LEDs and banana jacks , and 10mm for the toggle switch  .
2. Electric drill.
3. Soldering gun.
4. Soldering iron.
5. Wire cutter.
6. Electric tape.
7. Paper cutter.
8. Screw drivers (or whatever you need to take the ATX power supply apart).

My beloved electric Drill with metal bit

Steps:

• Open the power supply , and drill holes for 2 LEDs , 4 Banana connectors , and a toggle switch.

How my power supply looked when open

• All we need from the ATX power supply are 8 wires , they are :

1. Green : To turn the ATX power supply ON.
2. Purple : Connected to LED to show that the Power Supply is Plugged in .
3. Gray : Connected to LED to show that the Power Supply is turned on .
4. Yellow : 12v.
5. Red : 5v.
6. Orange : 3.3v.
7. 2 x Black : Ground.

• Once identified , cut all the remaining wires and wrap with electrical tape .

Testing power supply wires

Power supply with wires cut

Output of the Red wire in the power supply 

Toggle switch :

When the Green wire is connected to Ground the Power supply will turn ON. 

Connect the Black and Green wires to a Flat push-on connectors , On the Black wire side I connected the Black wire from the power supply board , and a free Black wire to Ground the LEDs.

Toggle switch 

LEDs:

Am using two LEDs a red and green , the green will turn on when the power supply is plugged in , the red will turn on when the power supply is turned on.

The purple wire will turn on once the power supply is plugged in , so connect :

Purple wire > resistor > Green LED > Ground .

The gray wire will turn when the power supply is turned on :

Gray wire > resistor >Red LED > Ground .

Output and Ground:

Connect each of the remaining wires to a banana female connector .

Banana connectors

Banana connector , toggle switch , and LEDs connected

My finished power supply