Turn Computer Power Supply Into Car Audio




Introduction: Turn Computer Power Supply Into Car Audio

This is my first instructable, so bear with me. I turned a computer power suppy into a 12v power supply for a car stereo deck.

Step 1: Getting Tools and Materials Together

Start off by getting:
Power Supply
Car Stereo Deck
Screw Driver (i used a drill)
Wire Cutters
Wire Strippers
Black tape
Beverage of Your Choice (I got a Diet Coke)

Step 2: Disassemblely of Power Supply and Wire Codeing

Start by taking the fan out, fallowed by the cover, next, find the green wire, you have to make sure the supply will turn on like it should. Plug the supply in and turn on the switch in the back (if there is one). Take a piece of wire and short the green wire to any black wire. These are located in the large motherboard connector. If the internal fan turns on, you are all set. If not, this particular model probably needs one or more of the voltage supplies (either the 12v, 3.3v, or 5v) loaded somewhat for the circuitry to work. I took a switch and wired it in because my power supply does not have a switch.

Wire Coding:
Yellow = 12v
Red = 5v
Orange = 3.3v
Black = Ground

I only needed 12v so i only used yellow,green and black.

Step 3: Wiring the Stereo Deck

Here there should be an red and yellow wore coming out of the deck, those two go to a yellow wire from the deck, the orange is for the display lights, and the yellow is for overall power. Hook up your speakers as normally, and enjoy.

Step 4: Final

Finally, tape all your wires, check your wiring, plug in and see if it works, if you turn the power supply on and the internal fan comes on but the deck does not, try to find a power button on your deck, if that doesn't work un-plug your power supply, wait 10 minutes for the capacitors to drain, and check your wiring. if that still doesn't work, either your power supply is no good, or its your stereo deck.

Video will be up very soon.



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    37 Discussions

    More common is that some power supplies require the 5v always on rail to have a load. So basically if you put a bulb or a decent 10w resistor between purple and ground then try to touch green+black... then the PSU will turn on. I had this issue and got it working. Took a lot of Googling. In then end I just got another PSU because it's a pain to wire up.

    Jump the green and black wire on the motherboard hookup, it'll turn on then

    Some power supplies require an ACPI signal from the motherboard. I'm sure that can be shorted to not require ACPI, but that's over my head.

    Dear Revotrx3 thanx for ur sharing... But i have lost my harness and also harness diagram.... I think my car stereo's harness matches ur one.... So, i would be grateful if u send me ur harness diagram....My email is binodpanda66@gmail.com ...Thank you...

    Nice job! :) I am almost there too, but at the moment I have PSU connected to car stereo. And there is an issue already. Through the speakers there is loud noise - audio volume doesn't affect it. Noise is there when I play music from my laptop using 3.5 audio cable And laptop is connected to the mains for charging.

    I think that's what's called ground loop noise. And people suggest buying ground loop isolators for audio cables (typically RCA). Or one can build it with two 600 Ohms transformers with 1:1 ratio.
    But! People also say that it reduces audio quality. Which I would like to avoid if I can.

    SO. I wonder could I break my ground loop where I connect PSU to Car Stereo (12v and ground)?

    Any suggestions? Does your emit noise under the same conditions?

    1 reply

    plug your laptop into an outlet that goes back to a different circuit than the psu is connected to. I have had luck with that but had to use an extension cord

    Watts / Volts = Amps

    So if it's a 200 watt Power Supply Unit (PSU) and you're pulling 12 volts

    200 watts / 12 volts = X Amps = 16.667 Amps

    If you want to know what each wire means, go to my website.:
    The image for the wire meanings is at:

    Is it possible to power a car amp with a server power supply? Server powers supplies are way cheaper. thanks

    I know no one has commented in a while but I feel I need to explain the shorting of the green wire (grey on some dells) with the black ground. doing so is the same as pressing the power button on your computer.

    You need to look at the AMPs that the 12v rail puts out. Usually they are around 14 or less for little power supplies. You should get one that is at least 25, and you still wouldn't be able to use the radio to its fullest potential then. Around 30-50 would be great, but that can get expensive.

    <p>Hey !!! if u need a power supply for this project you can usually find one on ebay for like 1 or 2 dollars but u cant allways buy right away =(</p>

    I used a 150w supply once to power my basic Sony radio, and if I turned up the volume a little over a quarter, the PSU cut out, which was a pain in the butt as the speakers I use are rather weak and need good volume to be able to hear anything... :( Plus the fan is (well, was, the PSU is dead) annoying, I like quiet when I have music playing, which is why I often wear my headphones, but a radio is handy to have by the bed... :)

    2 replies

    You could wire in a switch on the + wire that goes to the power supply's fan so that the fan would only run when you turned the switch on, but I wouldn't sugest running like that for long.

    That is true, but as you say, it might not like it for too long and would cut out. A thermistor and a relay could work for this, when the thermistor gets hot, it turns on the relay and the fan, and when it's cool, cuts the fan off... :)