Chosen Solution
Hi Device I traded in with broken/cracked LCD showed no signs of life. An lcd and battery change has got phone working however a strange issue I’m wondering if anyone has experienced before. When I connect home button/heat shield flex to the board the screen goes black. Presumed there was an issue with flex but is is the same once replaced and the same with other lcds. Any tips be appreciated, I’m guessing pointing towards board FPC issue. *UPDATE: Error disappears when home button is unplugged from shield.
You definitely need to inspect the Home button FPC on the logic board. It could be damaged and shorting out. But it could also be a defective Home Button that is shorting the circuit. If the FPC looks good and there are no issues with the surrounding components, then I would try to install a “regular” Home button (Touch ID will not work). If that solves the problem, it is either the button or the Mesa circuit (which drives TouchID functionality). Ultimately, the logic board will have to be tested by a micro-solderer to understand the root cause. If it is the MESA circuit, that can be repaired to restore Touch ID.
