A Technician’s Journey: The Revival of an iPhone 14 Pro

In the heart of the bustling city, nestled between towering buildings, lay the renowned REWA Lab. The lab had earned its reputation for solving some of the most intricate electronic problems. Today, it faced a new challenge: an iPhone 14 Pro that refused to turn on. The owner, distressed and desperate, handed over the sleek, lifeless device, hoping the technicians could breathe life back into it.

The technicians at REWA Lab, seasoned and skilled, wasted no time. They pressed and held the power button, waiting for a flicker of life. Nothing. Undeterred, they connected the charging cable, but the phone remained stubbornly unresponsive. It was time to delve deeper. They carefully disassembled the phone, disconnecting the battery flex cable. As they connected the power cord, they noticed a high current even before attempting to turn the phone on—a clear sign of a short circuit on the motherboard.

The first step in their diagnostic journey was to check the three main power supply circuits: BATTVCC, PP VDD MAIN, and PP VDD Boost. They referred to the bitmap, a detailed circuit diagram, and found the BATTVCC position. Using a multimeter, they measured the circuit, finding it normal. However, the PP VDD MAIN circuit wasn’t so forgiving—it was short-circuited.

According to the bitmap, the PP VDD MAIN circuit spanned both the logic board and the signal board. They needed a more precise diagnosis. Utilizing an infrared thermal camera, they powered the motherboard and observed an abnormal temperature spike in its center. The culprit was clear: the problem lay in the PP VDD MAIN circuit.

The technicians knew they had to separate the motherboard for a thorough inspection. They brushed it with PCB cleaner to assist in removing the protective foam, then used a hot air gun to heat and peel off the thermal sticker on the back. With the motherboard secured on a desoldering platform, they heated it to 170℃. Carefully, they pried apart the logic board and the signal board.

Their meticulous testing revealed the short circuit on the logic board. When they powered the logic board’s PP VDD MAIN circuit, they pinpointed the problem: the power IC. It showed signs of burning and cracks—a clear sign of failure. Replacing the power IC was their next task.

The technician’s hands moved with precision. They used a hot air gun set to 340℃ to remove the power IC’s edge glue, followed by a sculpture knife to lift the IC. After applying a bit of solder flux and medium-temperature tin, they used a soldering iron at 380℃ to neutralize the pads’ melting point. With a soldering iron and solder-wick, they removed the old tin and cleaned the pads with a brush dipped in PCB cleaner.

Repairing the damaged components around the power IC was a delicate task. Once ready, they applied a small amount of solder flux to the power IC pads and used a hot air gun to heat and solder the new IC in place. After rechecking the PP VDD MAIN circuit with a multimeter, they found the diode value normal, a sign of success.

Next came the intricate process of reballing the signal board. They applied a layer of low-temperature solder paste evenly and heated the signal board on a platform at 170℃. After the solder balls formed and the motherboard cooled, they applied flux paste to the pads. Carefully aligning the logic board, they continued heating until the boards were seamlessly combined.

Cooling down the motherboard with a dust cleaning air gun, they reattached the protective foam and thermal sticker. With anticipation, they installed the motherboard back into the phone. Connecting the screen and the power cord, they pressed the power button. The phone sprang to life, its screen glowing brightly.

The owner, overjoyed, tested the phone’s functions. Everything was normal. The REWA Lab technicians had done it again. They knew that beyond the technical skills, this job required patience, precision, and a deep understanding of electronics. They had not just repaired a phone; they had restored hope.

As the day drew to a close, the technicians reflected on their work. Motherboard repair, especially desoldering and soldering power ICs, was a challenging task. Yet, it was their passion. They thrived on these challenges, continually honing their skills and sharing their knowledge.

For those eager to learn more about such repairs, the technicians recommended visiting Gadget Kings. This platform, much like REWA Lab, offered insights into the world of electronics repair. It was a community where enthusiasts and professionals alike could share their experiences and learn from one another.

As the lights dimmed in the REWA Lab, the technicians packed up their tools, ready for whatever challenge awaited them the next day. They knew that each device they repaired was more than just a gadget; it was a story, a connection, a lifeline. And they were the ones who ensured these stories continued.