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The IPhone lights up both the OEM and amazon screen. All other features work expect touch screen... Where do I start? Get PCB schematics?
Thanks for any help..
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You will be able to locate the problem by measuring the pins on the touch FPC connector. Measure in diode mode with “red probe on ground” and compare with known good board or board view software.
There is a zero Ohm resistor that sometimes fails. This is located on the pin 1 line.
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If neither screen is working, my suspicion is that there was some damage to the board.
If at any point in the process the screen was plugged in, or unplugged when the battery was connected, voltage could have been bridged into an incorrect line and blown out a filter. It's a super common occurrence. It used to be most prevalent on backlight lines, but it can also happen to touch, or image lines. Especially on the iPhone XR this would be easy to do because the battery connector is under the flex cables for the display (I actually dislike the layout quite a bit).
Usually these blown filters are visibly damaged, they're just very small. And covered in a bunch of silicone. But you may be able to see some signs of heat/burn, a microscope or some sort of magnification would certainly help. But I would wager that's the issue. The connector I would be suspicious of is the one further from the battery connector. Any of the components in this picture labelled FL would be on my list of ones to check, but the ones in the lower right hand corner would be the highest on my list since those are for power.
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A little more history might help. If I read this correctly, you were swapping out the battery and after the repair you get no touch, even with multiple screens? Is that correct?
crwdns2934271:0crwdnd2934271:0 Alisha C crwdne2934271:0
That is exactly what happened. Phone lights up fine.
crwdns2934271:0crwdnd2934271:0 westman crwdne2934271:0
any ideas? @flannelist
crwdns2934271:0crwdnd2934271:0 westman crwdne2934271:0