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Guides for the Wi-Fi version of the iPad Mini 3 (A1599). Announced on October 16, 2014, the iPad Mini 3 is the successor to the iPad Mini Retina (now known as the iPad mini 2).

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Touch Not Working after Digitizer & FPC Connector Replacement

I’ve got an iPad Mini 3 WiFi (A1599) that belongs to a friend of mine that I'm working on. A few months back they dropped the iPad and it cracked the digitizer in the top right corner by the power button. They asked if I would repair it which I agreed to do. I replaced the digitizer and all was well.

A couple weeks ago they called and told me that the Digitizer was starting to lift in one of the corners. I told them no big deal and that I would re-tape the digitizer. This was partially my fault as I should have re-taped the replacement digitizer with my Tesa tape when I originally installed it, instead of leaving the garbage adhesive that came on the digitizer. But I despise working on iPads and just wanted to get it back together and off my workbench as quickly as possible. =p

So I got the iPad a couple days ago and disassembled so that I could remove and clean the old adhesive. I applied some new adhesive and proceeded to test fit the LCD & digitizer so that I could do a final test before final re-assembly. At this point I booted up the iPad and noticed that the Touch wasn't working. The Home Button and everything else was fine, but the digitizer was not responding to touch. So I attempted to re-seat the digitizer connecter when I noticed that a couple of the contacts were missing from the Digitizer FPC Connector. I replaced the FPC connector with a new one, booted up the iPad but still, No Touch! I swapped the digitizer with another one I had lying around but still, No Touch!. I also checked each leg on the FPC Connector with my multi-meter, and each one is making contact with the pads on the board, so I’ve ruled that out also.

I've never come across this issue before and was wondering what else I can check and/or replace to get the touch working again. Perhaps an IC or filter that maybe got shorted out when the FPC connector pins came loose?

Thanks in advance.

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The mini has a really poor quality Touch FPC connector and it’s quite normal for a few pins to lift when disconnecting the flex. That said, an FPC replacement is usually all that is needed. Continuity testing the pins is a good step but I also like to do a “push test”, meaning that I push on the leg (that is soldered to the pad) very lightly with a fine tip probe to see if there is any movement. If there is, you may have a weak connection and this could be causing issues.

I would also check the surrounding components as one may have been fully or partially dislodged. Finally, I would probe the pins in diode mode and compare to a known-good connector (the mini 3 digitizer FPC has a different configuration to than the mini 2 so you can’t use that).

Beyond that, it could be a Touch IC or Touch Power issue.

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The issue ended up being some of the legs not making good contact. The issue was when I was testing each leg with my multimeter, I was one lead to probe the connector terminal, and the lead to probe the pad on the board. But I realized that the clearance is so tight that I was inadvertently touching the leg instead of the pad on the board which was giving me false positive readings. So instead I ended up using Phoneboard to figure out where each leg goes on the board and ended up probing to those points instead of the solder pads. After I figured out which legs weren't making good contact, I ended up going over each leg one by one with my soldering iron and that ended up doing resolving the issue.

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Good job!! Yes, it is really tight in and around those connectors which is why I always check the solidity of each joint.

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