iPhones often fail to turn on due to a severe fall. Recently, a user reported that after his phone fell to the ground, pressing the power button did not respond and the screen did not light up. Today, follow PHONEFIX to see how to fix the iPhone 11 that cannot turn on due to a severe fall.
Disassembly and Inspection
After receiving the iPhone 11, the repairman first conducted a simple functional test and appearance inspection. Before disassembling, he turned off the phone, removed the two screws at the bottom, and then carefully pried open the screen with a Vacuum
suction cup and a crowbar. Because it was covered with waterproof glue, it needed to be disassembled slowly to avoid damaging the screen cable.
Disconnect the battery, power supply and screen cable, use 3D stainless steel tweezers to remove the motherboard for further analysis. remove the motherboard for further analysis. There are no obvious signs of burns on the motherboard, but because the iPhone 11 uses a double-layer motherboard structure (sandwich board), many hidden problems cannot be found by naked eye observation. In this case, further layer detection and circuit measurement are required to determine the fault location.
Disassembling iPhone CPU
After confirming a suspected motherboard issue, the technician proceeded to remove the CPU. A Soldering Station was used to preheat the motherboard, preventing board warping. Under a microscope, a heat gun was applied evenly around the CPU while flux was added to improve solder flow. Once the solder melted, precision tweezers were used to carefully lift the chip. Additional tools used during the process included an anti-static wrist strap, precison soldering iron, and desoldering braid to ensure safe handling and clean pads.
CPU double-layer separation:
To separate the CPU from the double-layer logic board, the technician first preheated the board using a BGA rework station to avoid board deformation. With the help of a microscope, flux was applied around the CPU area, and a hot air gun was used to evenly heat the solder joints. Once the solder reached the proper temperature, the upper CPU layer was gently lifted using precision tweezers. This process requires careful control to avoid damaging the pads or surrounding components. Proper ESD protection, including an anti-static wrist strap, was used throughout the procedure.
Inspection after delamination:
Take out the CPU. Using a Trinocular Stereo Microscope to observe the motherboard comprehensively, it was found that there were obvious signs of damage on the motherboard caused by a heavy fall. During the careful investigation, a key "heavy fall breakpoint" was identified, as shown in the mark in the picture. This breakpoint is very likely to be an important reason why the phone does not turn on.
Break point repair
Under a microscope, use a scalpel to gently scrape the insulating layer at the motherboard's break point, then clean excess solder with a desoldering wick and iron. Cut an enamel-coated wire, Solder Paste one end to a break-point side with flux for a firm joint. Route the wire along a suitable path, avoiding other components to prevent shorts, and solder the other end to complete the connection. Keep the wire untangled and slack. After soldering and cooling, apply insulating adhesive. Once dry, re-check the connection and insulation.
iPhone 11 Assembly
After the motherboard is broken and the wires are repaired and tested normally, start the installation. First, put the motherboard back into the iPhone 11 body accurately, carefully connect the battery, screen and other cables in turn, install the fixing screws, return them to their original positions and install other components, close the back cover and press lightly to make it fit, complete the installation, and then start the test.
Installation test
Reinstall the repaired motherboard back into the iPhone 11 body, and connect the battery, screen and other components. Press the power button, the phone turns on smoothly, the screen lights up, and enters the normal boot interface. Further tests of various functions of the phone, including calls, photos, Internet access, touch operations, etc., no abnormalities were found, indicating that this repair successfully solved the failure of not turning on caused by a heavy fall.
Conclusion
In iPhone 11 repairs, motherboard failures caused by heavy falls are common and complex. This repair successfully repaired the motherboard disconnection problem with the help of professional phone repair tools and phone repair parts, and accurately repaired the problem, allowing the phone to return to normal use. Phonefix helps you easily solve digital device problems and bring you a worry-free user experience.
