Remove the iPhone 12 Pro Max Display Screen and motherboard for testing whether it is deformed. The result turns on normally. Then we need to separate the motherboard for the pseudo-soldering.
Put the motherboard on the MJ CH5 heating platfrom for heating and pry up the logic board with a Pry Blade while heating. If remove the logic board when it is becomes loose. Then remove the signal board.
We find pads on the logic board are missing when we put it under the trinocular microscope.
2. Repair the Bonding Pads
Clean the bonding pads with Soldering Iron and clean the bonding pads with PCB Cleaner. Use a Sculpture Knife to Scrape the missing pads and pay attention not to damage the GND while scraping.
Put the Wylie Soldering Lugs in position and apply some Paste Flux. Apply Solder Mask to the bonding pads and solidify with a UV Lamp and remove excess solder mask with a Sculpture Knife.
Clean the bonding pads and reball the signal board. Attach the signal board to the holder. Put the reballing stencil in position. Apply some low-temperature Solder Paste evenly. Remove excess solder paste.
Reball stencil and put the motherboard on the Heating Platform. Remove the motherboard after it has cooled for 5 minutes.
Assemble and test the iPhone 12 Pro Max, and temperature warning disappeared.
If you notice your iPhone 12 getting hot when charging, unplug the charger. If you’re using a case with your iPhone, remove it. Turn off your iPhone and allow the heat to dissipate.
How to prevent overheating problem on iPhone 12 Pro Max？
1. Check your charger and use low power mode
2. Avoid hot environments and Get Rid of the Faulty iPhone Case.
3. Turn off Bluetooth, 5G, mobile data, WiFi, hotspot, location services, etc.
4. Close all background apps and Update software
5. Reset all settings