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Repair information and guides for the CDMA version of the fourth generation iPhone. Model: A1349 / 8, 16, or 32 GB storage capacity

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What is the correct backlight coil for iPhone 4 CDMA version?

I have an iPhone 4, 16GB, CDMA version which has lost its backlight after water immersion. I got iTunes to recognize after cleaning, but realized that the LCD/digitizer is toast, after replacement, and still nothing on screen I figured the backlight coil maybe IC was damaged. I believe I have correctly identified their location because I was able to swap the IC for one off an old 3Gs (a tad larger) and got my screen back! But no backlight :(

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Can someone verify I have identified the correct coil? Also can someone verify the coil and IC are the same in CDMA and GSM before I buy a set? I have not found much data online about the CDMA version iPhone 4 or backlight IC and coil swaps.

Thank you for any guidance.

New IC and coil didn't work

Ohh dear, back to the old drawing board. The IC and coil change did not improve the backlight situaiton. The iPhone's backlight is still not working correctly, I can see if I hold it under a light and I know it's loading into iTunes. What else is possibly wrong? I realized several other coils look like they might have had some water evap and maybe burns?

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Maybe try swapping them? Any further suggestions, I'm finding the CDMA iPhone or at least this one a bit more challenging to track down problems, but what else are weekends for. ; )

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you changed the IC, or the coil from "an old 3GS"?


Yes oldturkey03 I swapped out the IC with one from an old 3Gs (it is larger than the iP4 but fits) and got my screen back. I did that because I didn't have a spare for the iP4 and thought it would have a chance of working, and it did. But there is zero backlight so I don't know if I correctly identified the backlight coil, so I pulled my coil and put in the 6R8 from the 3Gs (in my photo that's the stock IC and coil), everything right now is much tighter, so I'm a bit stumped and looking for some suggestions.

I did restore the whole iPhone thinking possibly that might help me get my backlight going, but no. I did notice that my wifi is not functioning and am thinking that's from a dip in the water too and might need to swap that chip, but first things first.

I did order up a new IC and coil but everywhere I looked was not too specific and did not clarify it was for CDMA.


John Painter, at this point in the game, you really have nothing left to lose. I'd go for it and replace the other components as well.


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Oh I see you used the coil 6R8 from the 3GS but not the backlight, but not the backlight IC 109B from the 3GS. I have not worked on the CDMA so anything I tell you, is just speculation. What I would do is to replace the coil and IC \from the CDMA with a coil and IC of a GSM. They are readily available and much closer related to the circuitry of the CDMA than the 3GS.

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The major difference is how the "SIM card" is installed -- CDMA phones embed it on the motherboard, GSM phones allow it to be swapped. Other then this, there should be no differences in that regard. You can find the IC and coil as a bundle in many cases on eBay and other sites. It can happen where the coil dies, but not the IC so that may be an option as well.

As to what I think it could be based on what @oldturkey03 said I think the only change is going to be the embedded SIM card and CDMA radios -- the rest should interchange, but I'd use caution and double check if you want to be absolutely sure.

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Thank you nick and oldturkey03. I have ordered the GSM IC & backlight set and will be eager to see how it all works. I am familiar with the iPhone 4 GSM, both my wife and I have one, but when I got the Verizon version (somewhat on a whim) to see if there were any differences between how the phones worked off of their respective carriers - I managed to soak the CDMA phone and upon opening was unprepared for a very different layout of the mainboard. Heck I didn't even realize what the button style vibrator was at first. I was thinking why is there a pram battery in this thing??? LOL. Again, thanks for the guidance!


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1.) All those coils pictured look normal---coils have what looks like a burn mark on them naturally.

2.) Before any work is done on a coil or backlight diode, you have to first make sure that the backlight filters are intact---this is the most commonly damaged component after water exposure in any iPhone. If the filters are blown, you'll never get a backlight.

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John Painter sarà eternamente grato.
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