Double Laboratory Power Supply Reusing Old Recorders

I am a telecommunications engineering student, and i needed a power supply for prove the circuits i have to mount for practices. I didn't like going to university every time i had to do a test. Then, i found at home two old recorders and i thought to recycle it for to do a power supply!

The power supply can provide the following approximate voltages by combining outputs: 5 and -5, 6.5 and -6.5, 12 and -12, 17 and -17, 24 and -24.

I decided to put two power supply because in some circuits i need two differents voltages at same time, for different circuits.

Only you need:

Some old electronic equipment (dvd player, old pc, old tv...)

Some tools

Some patience

Good idea

some power supply terminals

LED, resistors (optional)

Buttons

Some wires, soldering tin

Open two recorders and extract the power supplies and the fans, its will be necessary for to cool the lab power supply. Test the different outputs for to know the different voltages you could have on it.

One of recorders i fully empty for take box for the project. It was aluminum box, very useful. Then, i put the power supplys in it.

The sources depended of a circuit for run, it wasn't easy to mount it, then, i examined the circuit of recorders for see which part was devoted to on/off the power supply and i cut that part for my new power supply.

I cut the box more or less in half, that could hold the two power supplyes and i putted it 4 pats for not to slice or clawed the tables.

The two power supplyes were at different boxes with different connections, then, i put the wires for to connections on the same box, but i joined it, for to connect two at same box's output.

I put two fans, one of each power supply, for to cool the box if it is much time working. I put two becaus if i need two differents voltages at same time, each power supply active one of they.

For to finish closing the box, i need some metal, then i bouht a sheet of aluminum, cut it and did the holes for differents voltage outputs, buttons and LEDs.

Also i cut an aluminum angle for the sides of box.

Put two power supplies in the box, screw clamps to the aluminum foil and conect the differents power supplies's outputs to the clamps.

I also put a red standard LED diode connected to 5V output via a 330 ohms resistor for each power supply, so you can know what source is active at each moment.

I connected fans to pin out for it (12V) and the activation circuit of each power supply, two activation circuit, one for each one.

Once time you had finished all wiring, you close the box and prove it!

Two power supplies are model, then both work equally, after the test, by combining the differents outputs, i can extract differents voltages: 24, -24, 17, -17, 12, -12, 6.5, -6.5, 5, -5.