Mobile phone repair is a delicate and professional task, especially when dealing with complex hardware issues. Today, Phonefix will share how to repair a Huawei Nova 6 5G with a baseband failure caused by being run over by a car. Through this process, we will not only understand the basic structure of a mobile phone's motherboard and common fault diagnosis methods, but also familiarize ourselves with some essential mobile repair tools and steps.
I. Fault Analysis: Symptoms and Causes of Baseband Failure
1. Symptoms of Baseband Failure
Baseband failure refers to a situation where the phone cannot connect to the cellular network during startup, and the screen displays "No Service" or "No Signal."
In many cases, users will find that the phone's communication functions are completely inoperative, and they cannot make calls or transmit data.
2. Impact of the Issue
The impact from a car run-over can often cause damage to the motherboard, especially to the baseband chip (the core component responsible for processing signals).
Even if the exterior appears intact, the internal components may still be damage.
II. Preparation Before Repair
1. Check the Phone's Exterior and Initial Diagnosis
First, check the phone's exterior to confirm if there are any visible physical damages, such as screen cracks or casing deformations. Next, check if the phone can power on. If it cannot, check for any battery issues. Use Digital multimeter to measure the capacitors around the baseband power to check if it's short circuit. Then, use diagnostic tools to check if the "No Baseband" error message appears. This can be confirmed through system diagnostics or by using diagnostic software.
2. Prepare Necessary Repair Tools
· Phone Disassembly Tools: These include suction cups, plastic prying tools, screwdrivers, etc., for disassembling the phone body.
· Multimeter: Used to check circuit continuity and identify broken connections.
· Microscope: To help examine tiny cracks and soldering points on the motherboard.
· Hot Air Gun: Used for heating and removing old solder points, especially important when replacing chips.
· Soldering Tools: These include a soldering iron, Solder wire, soldering pump, etc., for handling motherboard soldering issues.
III. Repair Steps: Disassembly and Fault Localization
1. Disassembly Process
· Remove the battery: First, power off the phone and remove the battery and SIM card tray to prevent short circuits during repair.
· Remove the phone casing: Use the suction cup and prying tool to remove the phone's casing carefully to avoid damaging the screen and body.
· Remove the motherboard and sub-board: Use a screwdriver to unscrew the screws holding the motherboard in place and carefully remove the motherboard. Generally, the Huawei Nova 6 5G has a structural separation between the main and secondary boards, so make sure to follow the correct order during disassembly.
2. Locate the Faulty Area
After removing the motherboard, use a YCS Trinocular Microscope to examine the baseband chip and associated circuits, especially for any visible damage or fractures. Check the soldering areas of the baseband section for any poor soldering or detached solder points. If there are cracks or uneven soldering, this could likely be the cause of the baseband failure.
IV. Repair Steps: Fault Fixing and Re-soldering
Step 1. Re-solder the Baseband Chip
If the baseband chip's solder points are confirmed to be problematic, use the hot air gun to heat the old solder points, soften them, and remove them. Use the soldering iron to re-solder the baseband chip's points. Be especially careful not to overheat, as this could damage the chip. During the soldering process, add solder wire to the soldering points, ensuring that each connection is even and secure. Use a microscope or magnifying glass to inspect each soldering point, ensuring there are no cold joints. Also, make sure no solder balls or leftover solder cause short circuits, which could lead to secondary failures.
Step 2. Remove and Check the Sub-Board
Sometimes, the connections between the motherboard and the sub-board may also be affected, causing signal transmission issues. Therefore, it is necessary to disassemble the sub-board and check for poor contact or broken lines. Use the multimeter to test the various connection points to confirm the circuit's integrity. If any issues are found, repair them promptly.
Step 3. Check the Mid-layer Connections
Disassemble the mid-layer connections of the phone and check for any broken wires or faulty chips. If necessary, use solder to reconnect broken circuits or replace damaged components.
Step 4. Test the Repair Effect
After completing all repairs, reassemble the phone, insert the battery, and power it on. Test the phone to ensure it can connect to the network and that the "No Baseband" error no longer appears. You can use system diagnostic tools to perform a detailed check and confirm that all functions are restored.
V. Conclusion
The baseband failure in the Huawei Nova 6 5G caused by being run over by a car is typically due to damage to the baseband chip and related circuits. By disassembling, inspecting, and re-soldering the motherboard, this issue can be effectively repaired. If you're interested in mobile repair tools or related information, feel free to visit China Phonefix.
