Qi Charging on a LUMIA 1520 AT&T phone (Solution)

[Benny Vallejo]

Hey, Jason -

I did have a look at this many months ago, but the key difference here is that the 925 was made to support both PMA and Qi-compatible charging back covers, and although the pin spacing on the 1520 looks very similar to the pin spacing on the 925 covers, it is unfortunately not the same. The 1520 has a wider spacing than the 925 cover, so folding over the flex to form a pressure-contact isn't going to work. Additionally, I think the pinouts are different, but I never confirmed that detail 100%. Both PMA and Qi-compatible cases are available for the 925, but there are no plans to release a Qi-compatible cover for the AT&T 1520, because that specifically goes against AT&T's release agreement with Nokia. Nokia's work-around for that was to release the International 1520, which as we all know, has Qi-charging support built-in.

The goal here was to find a way to support Qi-charging on a device that is specifically designed not to support Qi-charging, per AT&T's requirements.

As of yet, I haven't been able to locate a self-contained Qi-coil that has pinouts that directly match the pin arrangement and spacing found on the back of the 1520. I don't know where they came up with the pin spacing used, but I'm absolutely certain Nokia designed the 1520 pin spacing to be intentionally non-compatible with the existing Qi-charging covers. As I typed earlier, I think they also dicked with the polarity and trigger on the pin arrangement as well, but I'm not certain of that. I abandoned this path after I found the pin spacing was several milli-meters different.

Now, that said, there is nothing that keeps you from buying a PMA charging cover for the AT&T 1520, gutting the PMA coil out of it, and replacing that coil with a Qi-compatible coil. That would at least let you have the Qi-charging capability without opening your 1520, but you're still going to have to solder the Qi-coil to the PMA cover's flex somehow...

So, the short of it is that I haven't found a way to do this solder-free. Apart from pre-building the mods and selling them, I don't have a reasonable alternative for how to get around at least some soldering.

I'm always looking for improvements, so if I figure out how to get around this requirement, I'll definitely post something here.

Cheers,

SonarTech

@Sonartech. I was able to remove the larger qi coil from the international case and re solder it on to the 920 coil, of course by removing the smaller one. I'm not sure if it the charging time varies by doing this but it does seems to charge pretty fast. and i don't have to continually re-position the phone at all since the coil is quite large and made for the 1520. Also, it doesn't hurt that the international case looks good without 3 empty holes in the back (i used the 3 pins to solder instead of the flex cable and tucked them back into the case). So, in my opinion, it worked out for me to buy the international case since i used the qi coil from it as well as the case. Thanks for all of your help by the way.

 

[cporta]

Benny, can you elaborate on the method you used. I have the international case as well. Where did you solder? Did you use 3 wires? 1 positive and two negatives? How did everything fit in the international case?

 

[Citizen X]

@Sonartech. I was able to remove the larger qi coil from the international case and re solder it on to the 920 coil, of course by removing the smaller one. I'm not sure if it the charging time varies by doing this but it does seems to charge pretty fast. and i don't have to continually re-position the phone at all since the coil is quite large and made for the 1520. Also, it doesn't hurt that the international case looks good without 3 empty holes in the back (i used the 3 pins to solder instead of the flex cable and tucked them back into the case). So, in my opinion, it worked out for me to buy the international case since i used the qi coil from it as well as the case. Thanks for all of your help by the way.

Any chance you can provide some pictures showing what you did?

For example what exactly was your procedure for removing the coil from the 920 charging circuitry?

 

[NoRomBasic]

@NoRomBasic... I was also afraid to ruin my flex cable once i opened up the phone and saw how thin and tiny it was. In no way was i going to attempt to butcher it. Instead, i went with soloist_huaxin's suggestion and just soldered the 3 pin connections on the bottom of the flex to the 920 qi coil. the outer 2 negative and the middle one positive and voila! It will be a lot easier in my opinion to remove the solder from the 3 pins without literally hacking away into the actual flex cable. Just a heads up next time.

Thanks Benny,

I like your idea. I'm considering some different approaches when I get ready to take a shot at it again.

- Michael

 

[Benny Vallejo]

Any chance you can provide some pictures showing what you did?

For example what exactly was your procedure for removing the coil from the 920 charging circuitry?

I'll see if i can post some pics later on when i have some more free time. As for removing the coil.... if you see on the back of the 920 replacement coil, there are two little prongs sticking up with a tiny bit of solder on it connecting it to the circuitry. i used the soldering gun to melt the existing solder. Before doing this though...you have to carefully remove the actual coil from the black adhesive that envelops it. once it is removed from the adhesive, and the only thing connecting it is the two prong, you can then melt the solder while at the same time pulling it away from the circuitry carefully. Now do the same thing to the flex cable with the larger qi from the international case and just swap them. You may need to add a bit more solder to the 920 that you have removed. Not alot though....maybe just tin the tip of the qi prongs. then re-melt them once you place it on top of the 920 circuitry.

 

[Benny Vallejo]

Benny, can you elaborate on the method you used. I have the international case as well. Where did you solder? Did you use 3 wires? 1 positive and two negatives? How did everything fit in the international case?

I soldered the 3 pins at the bottom of the U.S. flex cable to the actual replacement 920 qi. Yes, i did do 3 wires. 1, for the middle pin for [+], then I solder the two outer pins for [-]. I routed the [-] wires to create 1 connection to solder to the 920 qi coil. remember to pre-tin your wires before doing this. Also if you are thinking about soldering directly to the pins like i did, take Sonartech's advice and DO NOT put the soldering gun directly on the 3 pins as they will fall off after long exposure to the heat. Pre-tin the wires and then melt the solder to have it fall off onto the pins. As for arranging the wiring on the inside, it may take some time but use as short and as thin of a wire as possible, do not leave too much slack as it may take up too much space and leave a bulge that is noticeable from the outside of the case. It took me a few tries but once i got it, it fit perfectly. The hardest part is making room for the 3 pins to fit inside the actual case. Try and solder the wires to the side of the 3 pins instead of directly on top and very carefully...that should give you a lot of room. I tried the top of the pins first which resulted in that bulge i spoke of earlier.

 

[NoRomBasic]

Well, after getting a hold of a Multimeter and takinganother stab at it today, I think I’ve got it working. The solution is ugly (basically because I didscrew up the PMAFLEX cable and had to work around that) but I can place it on aNokia QI Charger and it will charge (at least it has 3 times so far). For some reason it won’t establish a chargelink with the Maxell dual-pad charger I’ve got but that isn’t the 1[SUP]st[/SUP]time that charging pad has been fussy (it wasn’t fond of the Lumia 822 either) so I'm more inclined to blame the Maxell unit.

I’ll give it a few days here and see how it works overallbut so far it appears that I’ve got the “Unicorn” I was looking for (ATT LTEBands, 32GB, and QI Charging)

 

[NoRomBasic]

Well, after getting a hold of a Multimeter and takinganother stab at it today, I think I’ve got it working. The solution is ugly (basically because I didscrew up the PMAFLEX cable and had to work around that) but I can place it on aNokia QI Charger and it will charge (at least it has 3 times so far). For some reason it won’t establish a chargelink with the Maxell dual-pad charger I’ve got but that isn’t the 1[SUP]st[/SUP]time that charging pad has been fussy (it wasn’t fond of the Lumia 822 either) so I'm more inclined to blame the Maxell unit.

I’ll give it a few days here and see how it works overallbut so far it appears that I’ve got the “Unicorn” I was looking for (ATT LTEBands, 32GB, and QI Charging)

Yup, after 3 days I'm going to declare this fixed. I officially have a 1520 "Unicorn" edition (32GB, ATT LTE Bands, Internal QI Charging). Thanks to everyone on this group for all the suggestions, images, documentation and experimentation. If Nokia can fix the touch/swipe issue here soon as far as I'm concerned this is the best phone I've ever owned, Even where it is at though I'm not parting with it anytime soon.

 

[CollinFX45]

Yup, after 3 days I'm going to declare this fixed. I officially have a 1520 "Unicorn" edition (32GB, ATT LTE Bands, Internal QI Charging). Thanks to everyone on this group for all the suggestions, images, documentation and experimentation. If Nokia can fix the touch/swipe issue here soon as far as I'm concerned this is the best phone I've ever owned, Even where it is at though I'm not parting with it anytime soon.

Do you mind sharing where you got it? I have been desperately searching as well and I'm ready to trade a kidney for one.

​-Collin-

 

[Benny Vallejo]

Do you mind sharing where you got it? I have been desperately searching as well and I'm ready to trade a kidney for one.

​-Collin-

This is a mod that has been described in this post. You have to physically open up your phone and do it to make it charge wirelessly.

 

[NoRomBasic]

Do you mind sharing where you got it? I have been desperately searching as well and I'm ready to trade a kidney for one.

​-Collin-

Collin,

Right now you cannot buy one (hence the "Unicorn" designation), you'll have to make it or get it made. I'd suggest reading the whole thread here, especially anything posted by Sonartech. While I was reluctant to do so as I'm worried I'll lose my official "modder" card I'll include two pics of my modded 32GB ATT 1520. One with the incredibly ugly mod after I frakked up the PMAFlex. and the other with the 1520 resting on a Lumia Charging plate happily topping off the battery.

At this point if I were to do it again, I'm 100% certain I'd be able to do it a lot cleaner and with no mistakes (the benefit of experience). The one thing that I did choose to do differently than Sonartech is that I "flipped" the 920 QI coil/circuit so that the coil was pointed towards the top of the phone and the charging circuit was pointed towards the bottom of the phone. This allowed me to place the coil in nearly the perfect position for resting evenly on the Nokia charging plate while still getting nearly 100% of the 920 coil assembly in the recessed area where the original phone lay.

AND if I had had an intact PMAFlex (which I didn't due to my ineptitude) I would have run the jumper wires from the 920 Coil and soldered them closer to the base off the PMAFlex instead of the top (as suggested by Benny). I suspect this would have been a cleaner/easier install but since I likely won't be doing this again anytime soon I may never know.

 

[CollinFX45]

Thanks guys, I totally misread the last post! Thought yu meant that you gave up and found an RM-938

I was clearly wearing my unicorn goggles. I read all seven pages!

-Collin-

 

[NoRomBasic]

Thanks guys, I totally misread the last post! Thought yu meant that you gave up and found an RM-938

-Collin-

No Worries Collin. Believe me I'd rather have been able to purchase an ATT version of the 1520 with all the features Nokia originally planned for the phone myself. Would have been a lot easier.

- Michael

 

[jssmarathon]

If I were to buy the AT&T 32 GB version, does anyone know of anyone who would do this mod for me?
I would pay for their time and of course the extra parts and shipping. Bet somebody could start a business!

 

[Citizen X]

The one thing that I did choose to do differently than Sonartech is that I "flipped" the 920 QI coil/circuit so that the coil was pointed towards the top of the phone and the charging circuit was pointed towards the bottom of the phone. This allowed me to place the coil in nearly the perfect position for resting evenly on the Nokia charging plate while still getting nearly 100% of the 920 coil assembly in the recessed area where the original phone lay.

AND if I had had an intact PMAFlex (which I didn't due to my ineptitude) I would have run the jumper wires from the 920 Coil and soldered them closer to the base off the PMAFlex instead of the top (as suggested by Benny). I suspect this would have been a cleaner/easier install but since I likely won't be doing this again anytime soon I may never know.

Thank you so much. That picture was very informative. I was wondering about flipping the orientation and putting the coil connection closer to the pins. I got all the tools to hack into the flex but your butchering story scared me off. Anyway I need my phone for a work trip so it will be a couple of months before I sit down and do surgery on it. I don't want to f it up before I leave town.

 

[sadude69]

Benny...sorry if I am misreading but I thought you said you used the QI coil from the international 1520 case but your post is talking about the 920 coil Which one is it? If you could take some pics of the international case inside that we can acquire on ebay it would be very helpful as that would be the ultimate mod to use the international case and just attach it to the ATT internal cable and make it look PERFECT!

Nice job BTW...I am glad you were able to find a solution with all the input we have here!

 

[Citizen X]

Benny...sorry if I am misreading but I thought you said you used the QI coil from the international 1520 case but your post is talking about the 920 coil Which one is it?

He used BOTH.

@Sonartech. I was able to remove the larger qi coil from the international case and re solder it on to the 920 coil, of course by removing the smaller one. I'm not sure if it the charging time varies by doing this but it does seems to charge pretty fast. and i don't have to continually re-position the phone at all since the coil is quite large and made for the 1520.

No matter what you do if you want Qi you need a 920 coil. He just took it to the other level and swapped a 1520 Qi coil onto a 920 Qi coil circuit board... after he removed the 920 Qi coil. The swap is not necessary but it is a bigger coil and it may provide some advantages regarding positioning and charging time.

 

[Benny Vallejo]

He used BOTH.



No matter what you do if you want Qi you need a 920 coil. He just took it to the other level and swapped a 1520 Qi coil onto a 920 Qi coil circuit board... after he removed the 920 Qi coil. The swap is not necessary but it is a bigger coil and it may provide some advantages regarding positioning and charging time.

This

 

[inteller]

Are the contacts on the back of a stock 1520 not able to accept a Qi backplate?

 

[myrandex]

Inteller I asked a similar question earlier in this thread. Sonartech replied earlier and I forget the response but I think it isn't possible.

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