IPhone 12 Pro Max can't start the machine for repair

IPhone 12 Pro Max can’t start the machine for repair

Connect the mainboard with the power supply for repairing the machine, and the mainboard is very hot, indicating that the mainboard has a short circuit. This situation is generally caused by the breakdown of the filter capacitor, and the lower board is smoked with rosin, and then the power supply of the lower board repair machine is burned separately to lock the fault point.

Machine model: iPhone 12 Pro Max

Fault phenomenon:

The customer described the normal use of the mobile phone, but just put it on the bedside to charge it. The next morning, the black screen could not be turned on. The customer tried to restart it forcibly, changed the charger and connected the computer without any response.

Maintenance process:

After receiving the mobile phone, according to the customer’s description, we plugged in the charger and found that the charging current was 500 mA. When charging, we felt that the back of the mobile phone was obviously hot. Without saying anything, we directly disassembled the machine, took down the motherboard, and connected the motherboard with the power supply for repairing the machine. The current was about 5A directly, and the motherboard was seriously hot, indicating that the motherboard was short-circuited.

IPhone 12 Pro Max can’t be turned on for maintenance. Figure 1

This situation is generally caused by the breakdown of the filter capacitor. When the power is connected, the lower board is found to be hot by hand. The main board of iPhone 12 Pro Max is layered directly with an air gun, rosin is smoked on the lower board, and then the power supply of the lower board repair machine is burned separately to lock the fault point.

It was found that a small capacitor was damaged, so the damaged capacitor was directly removed. When the power was connected again, it was found that the motherboard was no longer leaking electricity, and a capacitor with the same specification was replaced. It was tested with a test bench and it was normal.

IPhone 12 Pro Max can’t be turned on for maintenance. Figure 2

After attaching the upper and lower motherboards, put them back into the mobile phone and start it up to test that all functions are normal and the fault is perfectly repaired, and the maintenance of this mobile phone is over.