Released on September 19, 2014, this 4.7" screen iPhone is the smaller version of the iPhone 6 Plus.

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Why Touch ID stops working after Meson IC repair

Any ideas on why touch ID (Fingerprint) stops working after a Meson replacement? I have tried a 2nd meson and still loss of touch ID. Restored in DFU with no change.

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Hey Michael. You will need to check the MESA circuit (U2100 / U1503) as well as all of the filters etc. They are directly opposite Cumulus/Meson and can be messed with when doing a Touch Disease repair. In some cases, the passives that are covered in epoxy (near the connectors) can lift right up from their pads and you will never notice it visually. So you have to probe and poke them to make sure they are making electrical contact.

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Both ic's,and several small caps. Filters and resistors had dislodged unter the underfill. Back up and running, thank you:)

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Awesome! Congrats!!

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Just noticed you had a similar issue with the Codec in another question. That means you are applying too much heat. Lower your temp (if you're over 380C), your airflow or time spent heating. Your goal is too apply only "enough" heat but unfortunately, it's a qualitative and not quantitative thing. You will get the feel for it with practice.

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Thank you @refectio , I have been using 360c to 380c with air flow around 4 or so. Not a great rework station but what I could afford for now and it is causing a few issues on trying to get to temp fast enough to get in and out. when it's a repair like Meson, Tristar, etc... it seems to go okay 90% of the time, but the other 10% is when IC shifts too much and having to do it a second or third time. Also a few I have had like Baseband, removing Sim slot, running traces, getting too much heat and having to do Tristar, I just end up going back and forth, lol... Causes secondary issues and a 30 min. job to 2 hours end up being 3 to 5.

But again, thank you for your help! I'm at about a 95% success rate on everything that comes by my desk...just slower than I'd like ;)

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