IPhone 12Pro Max phone has no baseband repair

IPhone 12Pro Max phone has no baseband repair.

Separate the motherboard, check the solder joints of the motherboard to see if there are obvious virtual solder joints, and then measure the solder joints from the motherboard to the upper layer. It is found that the main board has obvious solder joints falling off. After the solder joint is repaired, the measured resistance is normal. Re-attach the upper and lower layers, and repair the fault.

Machine model: iPhone 12Pro Max

Malfunction: The mobile phone has no baseband.

Maintenance process:

An iPhone 12 Pro Max, all functions of the mobile phone are normal, but the serial number of the baseband chip cannot be read.

All functions of the mobile phone are normal, and the serial number of the baseband chip can’t be read, which proves that there is a problem in the lower layer of the motherboard, or the middle layer pad drops.

Open Xinzhizhao and find the bitmap of iPhone 12Pro Max. The motherboard of iPhone 12Pro max is divided into two layers and three sides. Generally, some signal failures are caused by lower layer failures.

IPhone 12Pro Max mobile phone has no baseband maintenance figure 1

Separate the motherboard, check the solder joints of the motherboard to see if there are obvious virtual solder joints, and then measure the solder joints from the motherboard to the upper layer.

IPhone 12Pro Max mobile phone has no baseband maintenance figure 2

After inspection, it is found that the main board has obvious solder joints falling off. After the solder joint is repaired, the measured resistance is normal. Re-attach the upper and lower layers, and repair the fault.