Bypass Your Broken Airport Express PSU With an USB Power Source





Introduction: Bypass Your Broken Airport Express PSU With an USB Power Source

Ever have an Airport Express (AE) that will not power up anymore? Most likely it is from a broken power supply unit.  The cause is usually from a bad 3.3v regulator and/or bad capacitors.  This guide will show you how to bypass Airport Express PSU and power it with USB power.  This will great if you want to use an 5v USB A/C adapter, power it off your computer, or use any other USB power source.

Here is a list of suggested tools and materials you might need:
Airport Express
Hand Saw
Soldering Iron, Solder
USB cable
USB Compact Flash card reader, $2 online (slightly smaller than the AE so it fits inside)
3 wires (2-3inch in length), one for ground, one for 5v and one for 3.3v.

Update: I changed the blue tape to white tape on the reassembly of the housing.

Step 1: How to Open the Airport Express Case

Use the hand saw and cut along the case seam of the Airport Express.  The seam is where the two pieces of the case is joined together. The depth you need to saw is 1/8 of an inch. You should stop right when the plastic breaks through and you can see the insides.  Go slowly as you do not want to damage anything inside.

Step 2: Disconnect the Power Cable

Once open, disconnect the power cable from the power supply.  There should be three ground wires (black), one 5v wire (red), and two 3.3v wires (orange).

Step 3: Test the CF Memory Card Reader

Use your multimeter and find the locations of the ground, 5v and 3.3v on your CF Memory Card reader.  I am using the CF memory card reader for two reasons. One, it provides me with an existing USB port. And, two, a CF card reader provides a 3.3v output.  AE runs on both 5v and 3.3v.  You can create your own 3.3v stepdown if you want. 

You can use your multimeter and test your power supply too. A word of warning, there is a risk of electric shock if you do decide to tinker with your broken AE power supply.

Step 4: Wiring

Disconnect the power cable from the AE.  Snipe off the connector that plugs into the power supply end, not the end that plugs into the actual the AE.  Twist the ends of each type of wire together so it forms one tip.  Extend the length of the ground, 5v and 3.3v wires by soldering the 3 inch wires.  You can pick your own colors, but ground is usually black, and power is usually red.

Step 5: Soldering Wires to CF Card Reader

Solder the ground wire to the ground spot on the CF memory card reader. Solder the 5v wire to the 5v spot on the CF memory card reader. Solder the 3.3v wire to the 3.3v spot on the CF memory card reader. You can test the CF card reader to see if the wires are carrying power.

Step 6: Testing the USB Power

Plug the power cable back into the AE.  The other end of the power cable should be soldered into the CF memory card reader now. Power up the USB CF memory card reader.  If everything went properly, the AE should light up.  You can run the Airport Utility to see if the AE is operational.

Step 7: Reassembling the Airport Express

Now just reassemble the AE.  I suggested 3 inches of wiring because you might need to twist the wires so everything fits correctly.  I positioned the USB port so its in the same spot old power cord opening.  Your reassembly might be different depending on how you soldered or the size of your CF memory card reader.

Step 8: Final Thoughts

Use white tape electrical tape along the seam to make the reassembly look cleaner. You might also want to glue the case.

Standard USB power outputs 500mA.  AE runs on 3.3v @ 1.3A and 5v @ .7A.  You could want to try higher mA source if you plan to run both the AE audio jack and AE usb port. 

Shout Outs/Thanks:
Chris for some of the materials. for inspiration.



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Just to note I tried this and it didn't work with the CF reader I had.

I had the 'N' version of the Airport Express which was fully working, and checking the power it only required +3.3v.

I found the +3.3v on the CF reader (either the card detect pin, of off of on side of an LED, which stayed at 3.3v until I plugged into the airport express.

Once plugged in it dropped drown to 0.5v, so I'm guessing that the CF reader can't cope with the power that the airport express if drawing :-(.

Tried with the a 1amp USB and off the laptop

For the newer APEs with 6 black wires, check out the following image.


why not repair the original power supply?

1) If the fuse is blown even change the ic DM0265R under the sink and the two capacitors 10uf 400Volt.

2) if it still not working replace any 100uf 10V capacitors that are burned (look under the white glue).

good luck

Hi everyone.

Tried to use this : Wingonneer USB to TTL Converter Module with Built-in CP2102

The only thing I get is the green light flashing once, and then nothing.

Does anyone have an idea on haw to fix it, if ever possible ?

Many thanks in advance !

cheers! thanks for sharing, I've used this instruction a bit as a reference repairing a broken Apple Airport Express A1264 54 Mbps Wireless N Router (MB321LL/A). It all started with accidental reboots of the router and then it would just power on, but won't even boot. I fixed it by opening it up with a knife instead of a saw - I just cracked the internal lockers, but the gap between two parts turned out to be way smaller then it would have been if I'd saw cut it through. Then I looked at the power supply half and found a capacitor that heated too much and even left some marks on a PCB. It was somewhere around 10V 100 uF 105 ˚C and that was clearly not good enough, so I replaced it with a 16V 100 uF 105 ˚C capacitor and actually assembled the unit back. Works just fine for a month or so already.

What specific CF card reader and why not one of these?


I'm doing this with a fully functional AEX first generation N (blue board) The power lines between the two boards are all black, but the first 3 are ground, the last 3 are 3.3V. So while the form factor of the first generation N is the same as the one above, the circuitry is much more aligned with the latest 2nd Gen AE (white AppleTV) with on board audio as opposed to snap chip.

Just in the process of taking my Airport Express apart too. First off my unit appears to be a slightly different revision than the above. First all the wires are black, ok, looking closely at the circuit board there is 3.3v on one side and GND on the other. Easy the side with 3.3v must be 3.3v. I pulled out the multimeter and dialed it to the continuity indicator, hmm, the 3.3v has continuity with the shielding. So I pulled out an old usb cable stripped it down to test if the 3.3v side has continuity with the black usb wire, yep, what about the usb shielding, yep. Crap that must be GND. Ok so the first wire is GND, which other wires have continuity with the first wire, the next to wires beep, so the the three wires from the 3.3v label are GND. No I start from the other side, the next two wires have continuity with that side. Well crap, there basically only two leads and one of them is almost certainly ground. So is there a short in there or is there only one positive lead? Is that lead 5v or 3.3v. The label on the circuit board says 3.3v so that would seem the safe bet, but the USB port needs 5v, and a DC booster would likely need a capacitor large enough to stick out of the shielding, where as a 5v to 3.3v voltage regulator could fit discretely on the circuit board.

Thanks for the research and writeup - Since I have no card reader with 3.3v output I have just added two a LM1117 IC to a 5V wall mount adapter to get both voltages.

However: the airport express wants a lot of power. I think at least a 1A 5V adapter is a must (but everyone with a RapsberryPi around probably has one of those)

What CF Card Reader did you use? and for some reason all 6 wires of mine are black.