White lines across the top of the screen and touchscreen unresponsive

Hi Jordan,

Welcome to touch disease. This single problem outnumbers all other iPhone logic board level problems combined.

While it took the independent repair community years to finally deduce the core problem (The HIFA_BSYNC line that connects to the meson touch controller chip), it is extremely straightforward to make a robust repair. The M1 pad under meson becomes loose/stretchy/weakened through the normal daily use of the phone. This is the manifestation of a design flaw that was present on day one—the logic board is screwed down into the relatively flexible/bendy housing which means that the board is subjected to flexion forces that it can not withstand. One the M1 pad which connects the HIFA_BSYNC line to the chip is sufficiently weak, the classic flickering grey/white bars appear at the top of the screen and touch stops working. This intermittent problem will become worse over time leading ultimately to no touch function at all.

The fix is to lift meson, reball it or swap it for a new one, but most importantly—-add a reinforcing jumper wire to the M1 pad under meson. This will solve the problem and immunize your phone from having a recurrence down the road. Most local microsolderers will have plenty of experience with this problem since most busy shops see it daily.