Introduction: Power Supply From Old PSU
In this instructable, i tried to explain how to make a desktop power supply from an old PSU with minimal cost. Most of the materials i use are parts that can be easily found or salvaged from broken or scrapped electronic instruments.
The reason for the selection of PSU is that it provides stable voltage-current and also it is free.
At first we decide what we need and start collecting materials. In my projects, generally i need 12V, 5V and 3V. Because of this i did not add variable voltage, voltage screen or other outputs on the PSU (-12V) etc.
I planned to avoid the time losses in future projects by taking different outputs (USB, Banana jack, spring loaded wire terminals) for 12V and 5V. For 3.3V, I only got the banana jack output.
Step 1: Getting Started
First of all, it is necessary to pay attention to safety because of strong capacitors in PSU. The energy hidden in it can be really annoying. Secondly, make sure that the cables are not plugged in during operation. Everyone is responsible for their own safety.
- 1 x PSU
- 1 x On / off button
- 1 x spring loaded double wire terminals
- 2 x Female USB jack
- 4 x Banana jack
- Soldering Iron
- Cable stripper-cutter
- Hot Glue
- X-Acto Knife
- Spray Paint
- Rotary Tool
If there is a label on the PSU, it can save time to note the color and voltage of the cables. In this case, i need the orange (3.3V), red (5V) and yellow or yellow/black (12V) cables.
Step 2: Opening Up and Planning
Let's open the case and get rid of the wire collectors, jacks etc. on the cables. Group the orange, red, yellow and black wires. We also need to green cable here as well to operate the PSU. Apart from these, we can cut other cables. Make the estimated placement of the sockets and mark the places will cut and drill, according to their dimensions.
Step 3: Cutting the Case
Cut and drill the marked places with the rotary tool. For USB sockets, we first drill holes and then rasp them to the size desired. If possible, it should be done this after completely removing the circuit board for without spilling metal shavings on the circuit board. This eliminates the possibility of damaging any cable or component.
Step 4: Customization
At this stage we add a little visuality to the power supply case. This step can be passed. After completely dismounting the case, i painted the bottom part black and the upper part yellow with spray paint and then left it dry. Then i got the printout the shape, i cut it and glued on the case and painted it again with black spray paint. After dried, carefully remove the templates.
Step 5: Wiring the On/off Button
It came up to connect wires. First we will connect the button that will allow us to turn on and off the power supply. Generally, PSUs can not be turned on when not connected to the computer motherboard. For this we need to connect green cable that we have previously reserved, and any of the black cables (GND). So we will be able to turn on and off the power supply without needing a computer. Green cable is soldered to one leg, and black cable is soldered to the other leg. I salvaged the button from an old broken extension cable.
Step 6: Wiring the USB's
After soldering the button, we cut the black, yellow, orange, and red cables in the appropriate lengths. After inserting the USB sockets, place one black cable together with red (5V) and yellow (12V) cables in the same way as in the picture. Fixed with hot glue to keep them in their places. I also salvaged these USB jacks from old burned phone chargers.
Step 7: Wiring the Banana Jacks and Spring Wire Terminals
For banana jacks and spring wire terminals, we group each cable in pairs. After putting the banana jacks together with the insulators in the openings we opened in the case before, we connect the cables in the order we want. Then we solder the yellow and red wires to the spring loaded wire terminal with black (GND) cables. In the images above you can see where I salvaged the spring loaded wire terminal. In this project, the only parts I bought were banana jacks.
Step 8: Testing
After connecting all the cables and putting the sockets in place, we do checks before closing the case. I already closed up the case before the checking but thankfully there is no problem about wiring. After the checking, i added labels on each socket.
Thank you for reading, if you like please vote.
PS: Sorry for my english :)
RobertC2 made it!
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Very well done Instructable! Thank you for sharing it with us!!
English is very, very good for a non-native speaker. I've spent much
time over many years trying to learn German and Spanish and could not do
as well in either language as you did in English.
articles on converting old PSUs to test bench supplies. All use the
standard +12V, +5V, and +3.3 V outputs used by most computers. I would
like to have also a 110-120VAC output. I could then plug my soldering
iron into the bench supply instead of having to find another workshop AC
outlet. It would, I think, reduce bench clutter some, too.
that such a modification is possible, how would you go about adding a
110-120VAC output? I realize I would need a female receptacle installed
in the case; but, being a real electronics newbie, I don't know how to
go about it. Would it be as simple as connecting from male input
receptacle pins or wires to the new female receptacle?
I'm considering for this project has an O/I switch beside the 110-120
VAC input receptacle. I think this would prevent power to the PSU in
the O position and allow power in the I position; so this leads me to
think that I might be able to wire from the switch to the female
receptacle. How would I be able to determine if the switch can handle
the pass through load for both the PSU and the output 110-120 VAC?
Again, thank you for this 'ible!!!