Matters needing attention before repairing mobile phones

Before repairing your mobile phone, you should pay attention to the following items:

  1. Mobile phones are microelectronic products of integrated circuits. Integrated circuits are precise and developed through advanced skills. Maintenance personnel must understand the functions of each chip and component equipment, understand the logical connection of circuits, and perform circuit repairs. Analysis, careful inspection, correct judgment, fast and accurate operation, to prevent misjudgment, human error, and economic loss. Ask the user whether it has been repaired before. If it has been repaired, ask the user what fault was repaired before, and judge whether the same fault has occurred again, so as to find out the scope and cause of the fault.     2. Carefully observe the shell of the mobile phone to see if there are cracks, scratches, and water ingress marks, and ask the user why these marks occur, so as to clarify whether the mobile phone has been dropped. Cracking, virtual welding and other phenomena, the mobile phone with water will show various faults, and it needs to be cleaned with alcohol or washing board water, 530. Mobile phones with severe water ingress and corrosion can damage integrated circuits or circuit boards.   3. Carefully observe whether the contact between the battery and the battery spring contacts is loose, and whether the contacts of the spring contacts are dirty. These phenomena may easily cause problems such as the mobile phone not turning on, and sometimes the power is cut off.   4. Carefully observe the information on the mobile phone screen to see if the signal strength value is normal, whether the battery power is sufficient, and whether the display screen is intact. Clarify the functions of the reception, transmission, logic and other parts of the entire mobile phone.   5. There is no signal strength value indicator on the screen of the mobile phone, and it shows faults such as checking the card, you can insert a good SIM card into the mobile phone first, if the mobile phone can work normally, it means that the fault is caused by a bad SIM card, if the fault of the mobile phone cannot be ruled out , indicating that there is something wrong with the phone circuit.   6. Connect to the test instrument as required, open the test instrument and set it correctly, and preliminarily judge the type and scope of the mobile phone failure. The printed circuit boards inside the mobile phone are inlaid with chips of different technical levels and levels, as well as new components, so do not perform maintenance operations under strong magnetic fields and high voltages to avoid being damaged by high current shocks. Maintenance operations must be carried out on an anti-static workbench. The surface, maintenance personnel, and workbench should be electrostatically shielded to be well grounded to prevent static electricity.   7. The workbench should be kept clean and hygienic, and the maintenance tool room should be complete and kept at hand. During maintenance operations, it is necessary to load and unload in a certain order, and the chips and components to be taken and placed should also be arranged in a certain order to avoid confusion. Keep the circuit board clean and free from manipulation, and prevent all solder, tin beads, wire materials, and conductors from falling into the circuit board to prevent other faults.   8. Different manufacturers, different models, and different styles have different version numbers. Use qualified and normal chips and components of the same version to avoid replacing chips of different versions. Do not use unqualified, pirated, or smuggled chips and components to avoid more complicated faults. Here, correctly analyze the circuit and correctly judge the error. It is very important to find the faulty part correctly to avoid misjudgment.   9. Pay attention to check whether the settings of the mobile phone are correct. Many mobile phone problems are caused by incorrect settings. You can restore the settings or flash the phone for detection.   10. After the maintenance is over, it is necessary to clean and tidy up the workbench. Let the maintenance tools return to their original positions, and reinstall all the accessories (long screws, antenna covers, rubber particles, insulators, etc.) to avoid missing a few things at a time. Maintenance personnel should master some basic terminology and common sense of mobile phone maintenance to judge the cause and general scope of the fault, and avoid testing one by one according to its principle or finding fault points on the entire circuit board.