## iPhone 14 Pro Max Repair: VDD_BOOST Failure & PMU Replacement
An iPhone 14 Pro Max arrived completely dead, drawing 0mA on the DC power supply. Initial diagnostics pointed to a critical short circuit on the primary **VDD_BOOST** rail.
1. Board Splitting & Inspection
The dual-layer logic board was separated using a heating platform at 210°C. As shown in pic, the top board was secured into a precision micro-soldering jig. Thermal imaging and voltage injection on the shorted line confirmed that the fault was localized directly inside the Main Power Management Unit (PMU)..
2. PMU Desoldering & Pad Preparation
With the CPU safely shielded from heat, the defective PMU was removed using hot air at 350°C. Factory lead-free solder was wicked away and replaced with low-melt leaded solder to lower the next melting threshold. The area was cleaned thoroughly with IPA. on the microscope monitor, the BGA pad matrix was cleared perfectly with zero torn or bridged pads.
3. IC Reballing & Reflow
A new OEM PMU IC was reballed using 183°C leaded solder paste. The chip was aligned precisely over the pad array and reflowed with hot air until surface tension centered the component perfectly into place.
### 4. Final Testing & Results
Diode mode readings on the VDD_BOOST rail returned to normal factory values. The logic board layers were resoldered together using the interleaving frame. The iPhone booted successfully into iOS, verifying full peripheral functionality and 100% data recovery.
