If there is one worthwhile criticism about the Nokia Lumia 1520
for AT&T, it is that the carrier opted to strip the device of its otherwise native wireless charging ability, in favor of selling an accessory that supported wireless charging using a standard different (PMA aka Power Matters Alliance) from what Nokia supports (Qi).
The battle for supremacy in wireless charging is far from over however. Qi is well established, but PMA is gaining acceptance and has some heavy hitting sponsors now backing its play, notably the aforementioned AT&T as well as Proctor & Gamble and Duracell (Powermat).
For Nokia owners though, it is frustrating because back in 2012 when they picked up an AT&T branded Nokia Lumia 920 and bought a Nokia Wireless Charging Plate to take advantage of the device’s wireless charging abilities, if they chose to upgrade to the Lumia 1520, they were out of luck, even if they bought an optional charging back from AT&T due to conflicting standards.
However, if you are determined to make good use of your Nokia branded or other Qi standard charging plate, and are not afraid to do a little operating, you can bring wireless charging capability to your AT&T Nokia Lumia 1520 and make it look like it came that way.
First, you will need the following:
- Original AT&T 1520 shell (to re-use the PMA cable)
- Nokia branded Lumia 925 wireless charging cover (not the Incipio PMA one)
- International Nokia Lumia 1520 replacement shell with Qi coil in it
- A soldering kit (and some skills to use it)
- Kapton tape
- Multi-mater to test continuity and voltage
- Liquid nickel conductive pen (optional)
The rest of the instructions we incorporated in the slide-show below. This solution is not cheap, but it brings that one extra feature to your device if you truly love it enough. Just in case you cannot draw the connotation, doing this to your AT&T Lumia 1520 (or any device really), will void the warranty, and if you pursue this endeavor, you do so at your own peril and risk. The end result in this case however, shows success, and while there is some skill involved, it is doable if you understand the parts involved. Let us know if you give it a try and try not to set anything on fire. If you get stuck, consult the source links below for help.
Qi standard wireless charging - AT&T Lumia 1520
Qi standard wireless charging - AT&T Lumia 1520
Step one: Preparation
1. Remove the back cover to your Lumia 1520 and carefully remove the existing flex cable. It's held with dual sided tape on the bottom and the top.
2. Take the coil out of the Lumia 925's charging shell. Peel off the layers and de-solder the coil from the circuit board (two wires connect the coil to the board, leave some solder on the board)
3. The voltage converter board has a black piece of plastic around the metal contacts, you can pry that off from the bottom (take it slow, it takes a little pressure, but will come off). You'll have the three prongs left.
4. Remove the three prongs on the voltage converter- Bend the metal contacts back and forth until they snap off (or de-solder them, but be careful not to apply too much heat. Pro-tip: leave a little hot solder on the tip of the iron and use that to heat the edge of the pad)
5. Now, with the new replacement 1520 shell, remove the flex cable and bend it backwards so you can see the contacts from the charging coil.
6. De-solder the coil from the flex cable and remove the flex cable from the shell. Leave the coil and shielding in place..
7. Place the voltage converter circuit on shell and line up the pads where the old coil was soldered, now solder the shell's coil wires to the pads.
8. Test the voltage place your multi-meter's leads on the left-most and right-most pins on the converter circuit board. You should be getting approx. 7 volts when the shell is on a charger. The pin to right is negative, the pin to the left is positive, the pin in the middle isn't used for our purposes.
Now this is what you should now have
3. Parts overview
Here's a high overview of what parts should be on your workspace
Now tape down your work with Kapton tape to secure and insulate it from the next layer.
5. Prepping the PMA cable for soldering
My next step was to short out the two negative flex paths. I like my liquid nickel pen for these low profile, low stress connections. When the liquid dries, just the nickel is left and completes the circuit because it is conductive.
1. Cut a couple small pieces of wire from the left-over Lumia 925 wireless charging shell's coil (the advantage of doing this is that one side of the wire is pre-tinned).
2. Pre-tin the exposed spots on the flex cable. This way when it comes time to connect the wire, its literally melt-and-go, no need for additional solder.
3. Pre-tin the cut ends of the wire (STOP - before continuing, make sure there continuity in the wire. If not, make sure you have properly tinned the wire (there is a very thin layer of nonconductive material so that the wire doesn't short when it's coiled. You can burn this off with the iron or scrape it off)
4. Line up and snap in the flex cable to the same spot it was on the original case (it will fit exactly). Secure the flex cable to the case with your non-conductive tape
5. Now solder the wires to the to the converter pins first, with them secured use tweezers to hold the wire down and solder to the right spots on the flex cable (read SonarTech's post). The left pin is positive and the right most pin is negative. Ignore the middle pin.
6. With the wires soldered, use your favorite non-conductive tape to hold down your work.
One last voltage test, put the finished shell on a wireless charger make sure you are getting 7 volts ( IMPORTANT make sure the polarity is correct before putting the cover on, otherwise you will fry your phone's charging circuitry )
8. Ta da!!
And here is the proof (I've had it on the charger for hours now. Thanks to the coil being engineered as part of the shell, it is in the right place and there is no improper heat displacement. In fact, I barely feel any heat).
source: WPCentral (1
credit: Lance McCarthy
(Twitter) - developer who outlined all the detailed instructions