iPhone 6s filling key causes the touch failure two repair process

Machine model: iPhone 6s

Malfunction: the screen of the mobile phone is out of order

Maintenance process: After getting the machine for visual inspection and touching BTB connector, the sealing glue of the small component next to it was picked off.

It is estimated that the temperature of welding plastic seat was too high, which caused Open to be repaired by itself. The screen change test is still Touch failure, indicating that it is not the screen.

iPhone 6s filling key causes the touch failure two repair process Figure 1.

There are some small components next to the touch pad that are not as good as welding, and they fall off after a little plucking with tweezers, so first fix the small components next to the touch pad, and the test failure remains the same.
It was found that the touch VCC IC was also moved. This chip is responsible for touching and displaying VCC at the same time. It is found that there is a missing corner in the chip, which is not good to see. Therefore, it is replaced, and the fault is still the same.

iPhone 6s filling key causes the touch failure two repair process figure 2.

Check that there are no other places on the motherboard that have been moved. Go back to the touch base and check the small components one by one. No Open is found. All touch related items are excluded. The touch chip is on the screen and the screen has been changed.diode value related measurement is normal,VCC measurement is normal, no maintenance ideas.
I have several 6S of Move Board (move the main chips to another motherboard)in my hand. I took one of them at random. After Move Board (move the main chips to another motherboard),Update System went smoothly and Boot was ready to be installed. When I was ready to install it, I wanted to check the touch working conditions.

During the comparative measurement, it was found that the PAD which should have been empty on the main board of Touch failure was replaced by short-circuit with the component number of r3144. This one was put up by the upper household tin short-circuit, which was not noticed at that time.This component is also not labeled nostuff on schematic, and it is 0 ohm resistance.