Wire a Car Stereo to a Computer PSU




This is the second case i have made. i am going to teach you how to mod your old computer case into a stereo and wire a car stereo to a computer PSU.

-wire cutters/strippers. (or just use a knife like how i did)
-needle nose pliers
-solder-less butt connectors (unless you plan to solder your wires)
-Computer PSU
-computer tower (or any other metal case)
-car stereo
-dremel or similar
-tape measure
-pop rivet gun
-a speaker terminal
-a drill

lights, plexiglass, etc.

it would be nice to have a jigsaw, like this- http://www.sears.com/shc/s/p_10153_12605_00917235000P , so i can make an instructable for a speaker box

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Step 1: Know Your Wiring

Wiring from PSU:

Wiring from stereo:
Red_____ign sitch
yellow___constant 12v

VERY IMPORTANT!!!!!!! In order for your psu to work when not connected to the mother board, the green wire MUST be connected to any ground wire.

if you wish to add a switch to the PSU so you dont have to unplug it all the time,
-carefully take apart the psu.
-be careful not to touch the capacitors.
-cut the blue wire (positive), strip it, and add a butt connector to each end of the blue wire.
-then connect enough wire to extend to the switch (depending on where you put it).
-connect the wire to the switch. i used hot glue to keep the wires from touching each other on the switch.

MAKE SURE YOUR MAIN POWER CABLE IS UNPLUGGED. i flipped the breaker when adding in the switch.

Step 2: Prepare the Case

the case i chose was smaller than the last time i built one. and i still am looking for even smaller cases. i was missing the side panel and so i chose to have the case lay sideways with a plexiglass cover.

it had a tray that was riveted in for the floppy disk. you can drill out the rivets to remove them.

then i used roofing and siding metal (corner pieces) that i got from the shop at school.
i measured and riveted them in place on the ugly side where i cut the tray from. (originally the front)

sand the case just enough to paint will adhere, but try not to sand to the bare metal. (unless you are painting a bright color)

Step 3: Measure Twice, Cut Once

measure the stereo side to side and up and down. i wanted to make sure i was dead center, so i measured and remeasured my markings. i waited until later to cut this out.

then i had to make a lip for the plexiglass, which wasnt big enough to cover the entire case. i used the metal material and made a lower lip. then to cover the horribly cut side of the plexiglass, i made an upper lip which pinched the plexiglass in place.

then i added extra support rails for the stereo

Step 4: Screw It

drill out holes to screw in the plexiglass. be careful not to tighten the screw too tight or it will crack the glass.

Step 5: Speaker Wire Management

i wanted to have easy access to the terminal in case of replacement. so i cut out a plate big enough to fit in the hole on the tower where the motherboard connectors were.

i then measured and used a dremel to cut out the place on the plate where the terminal would go. once it fit, i used screws (normal computer screws) to hold it in.

i then removed the terminal and attached colored wire to the pos and neg connections on the terminal. and once again hot glued them in place to prevent touching.

Step 6: Adding in the Radio

i am still figuring out a way for the stereo to be held in place so it does not move, but for now it stays in place. i also have to figure out my cable management for the power wires.

like ive said before, wire the green wire to any black. then attach this set of wires to the neg on the stereo, or attach any other black wire from the psu to the neg on the stereo. (it doesnt matter)

then attach the yellow and red wired from the headunit to the yellow from the psu.

and then attach a pos and neg terminal wire (make sure they are next to each other on the terminal plate) to the corresponding pos/neg wires from the headunit.

Step 7: More Touch Ups, Painting, and Accesories

i decided to paint the outside of the psu, so i took it apart, taped up the holes, and painted/clear coated.

i cut out a blank piece of metal for the other half of the opening and painted it as well.

i painted the whole case black, and painted the inside white for better light reflection.

i added in a fan that runs on a 12v wire. i ran the wires around the bottom to hide them for now.

then i added in lights. i wanted to use cold cathodes, but i figured christmas lights would work well. i wired in about 2 or 3 lights to a 5v wire and about 4 to a 12v wire.

Step 8: All Done. and My Other Stereo I Made

enjoy. one downside i have found is if you turn the volume too loud, then the psu will shut off. so all that is needed is a bigger voltage psu. mine is 250v.

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15 Discussions


9 days ago

Your: "one downside i have found is if you turn the volume too loud, then the
psu will shut off. so all that is needed is a bigger voltage psu. mine
is 250v" ....... is an incorrect and confusing statement.

The operating voltage of the PSU is not your problem.

The OUTPUT AMPERAGE is what you need to consider. 110VAC or 220VAC is just the supplied voltage from the power system with which your PSU or computer, is designed to operate. It has little to do with the Voltage, Amperage (and computationally the Wattage) output of the PSU.

Most PSU builders further confuse things by speaking of that Wattage... which is all fine and dandy, but the finality of the situation is that you need sufficient Amperage to succeed, if you know how to visualize the total draw of the radio you are going to operate.

The Voltage produced by the PSU must be constant within the drawn Amperage of its design, or the built-in safety factors in the PSU will shut itself down to prevent damage to itself and any other circuit that may be getting starved for power (Voltage).

You can usually read these capacities on the PSU enclosure itself, posted there by the manufacturer.


1 year ago

How strong is the psu?


8 years ago on Introduction

You could get a small 12v battery to connect to the constant/memory wire of the radio so you can save your settings.

5 replies

Reply 8 years ago on Introduction

Also, you can get a cheap soldering iron, and it is not difficult to solder. That would be better than hot-gluing the wires to keep them connected.


Reply 8 years ago on Introduction

im sure that you could. but i would make a switch so that you dont have both the battery and psu powering the headunit, otherwise 12+12=24v. i would have to go test out a way for it to work.

also, i didnt solder for 2 reasons.
1. i was inside while wiring this. it was about 100 degrees farenheit in my garage.
2. i wanted to be able to just cut the wires and reconnect if needed.


Reply 2 years ago

The connection would be in parallel, voltage only adds up if connected in series. Connecting a battery in parallel to save settings is absolutely possible.


Reply 8 years ago on Introduction

The Constant/Memory (Yellow) wire of a radio while installed in a vehicle always has 12v going to it. When the car is on, or while it is off. Otherwise, your radio would lose the saved settings. When you have a 12v constant source going to the Constant/Memory (Yellow) wire, and a 12v switched source going to the Ignition (Red) wire, it will not overload the radio. The red wire just tells the radio to turn on and draw power from the yellow wire.

Alright, its your project, I was just saying soldering is the best way, but I guess it doesn't really matter.


Reply 3 years ago on Introduction

Hi, i don't know if someone watch this thread, but i have a question about the Constant/Memory (Yellow) wire. If i connect this wire with the +5VBS on the PSU, can i keep the memory on ?

And how start the PSU when i start the car stereo ?


Sorry fo my english.


4 years ago on Step 8

Reason that it's shutting down could be because you're overloading the 12v rail. check the PSU's manufacturers site to see how many rails it's got, if more than one then find out which wires correspond each rail and join them all together to power it, lots of cheaper power supplies will have multiple 12v rails and can cause this to happen


5 years ago on Step 8

sir i have a problem about this.. please help me

i search in youtube about the
tutorial on how to power a car stereo using a
computer power supply, i cut the green, 2 black, 2
yellow wires from power supply, i connected the
green wire and black wire , and also the yellow to
yellow , on my car stereo i connected the yellow
wire to red wire. then i connected the black wire
from car stereo to another black wire from
computer power supply, and the yellow-yellow wire
from computer power supply to yellow-red wire
from car stereo then connects the other wires at
the speakers then plug the computer power supply
to the socket. the car stereo was on and playing
mp3 BUT doesn't sound. please help me , email me
on djovert_conquer@yahoo.com


6 years ago on Step 8

do you connect the speaker wires from the stereo to the wire terminal? and what are you using for speakers? im going to attempt to build my own homemade stereo but mine is going to be out of mdf wood.


8 years ago on Step 8

Well done, nice 'ible'. I would echo what others have said and suggest soldering the wires now that it is a permanent fixture, you'll get better conductivity that way. Have you considered putting a car stereo into a fully working PC? It shouldn't be too difficult and the stereo itself could go into a 5.25 bay possibly with a bespoke surround plate.

3 replies

Reply 8 years ago on Step 8

my teacher had the same idea of putting the stereo into a working pc. the last pc i had was built from scrap parts because i didnt have much money at all.

but also, one of the problems is that if the radio volume turns up too high, the PSU cuts power to prevent an overload. i wouldnt want that happening while browsing the web.

one optional way to fix that is a bigger PSU,


Reply 8 years ago on Step 8

Wow! I'm rather surprised that it was tripping out just by having the volume turned up. I'm sure I have read of someway of preventing this from happening possibly in another instructable. I shall certainly bare it in mind when (or if knowing me) I try this little mod :-)

Take care mate.



Reply 8 years ago on Step 8

let me know if you find out a way to bypass it.