As we know, the problems caused by dropping for the iPhone, there are two main reasons, one is the iPhone solder pad drops pins, and the other hand is the iPhone is short-circuited.
Use 3D screwdrivers to remove the screws next to the iPhone lightning port, and then use screen sucker to open the iPhone display screen. Remove the iPhone display screen, disconnect the iPhone battery, and then take off the iPhone motherboard.
Log in to ZXW dongle to check iPhone 8P schematic diagram and bitmap, and use digital multimeter to measure the resistance value for the iPhone IC solder pad, we found SCLK_HB_LB_DSM_FILT_E signal of the DSM_LB_E and DSM_HB_E chips are shorted.
Use hot air gun and tweezers to remove the resistor in the position of the C1602-E capacitor, and install it to the right position, solder the jumper wire to those pin that were dropped, and then install the IC to the motherboard.
Now install the iPhone 8P and test it, but the problem is still the same, the iPhone 8P still no service.
Disassemble the iPhone 8P again, observing it under the 7-45X Black Microscope, compare it with the iPhone schematic diagram, we found that the FL1501-E inductor was missing.
Finally, turn on the iPhone 8 Plus, insert the SIM card, the signal is back, the iPhone 8 Plus got the service.
Hope the above method is useful to you. If you have other maintenance ways, please leave us a message in comment.