Nowadays, there are more and more mobile phone users, and the phenomenon of mobile phone failure is also diverse, although there are more mobile phone models and different structures. However, the maintenance methods are roughly the same. ORIWHIZ introduces some common maintenance techniques for reference by beginners and mobile phone enthusiasts:

Inquiry method

When you get a faulty mobile phone, first ask the user under what circumstances the fault has occurred, whether it has been repaired, etc., according to the user's reaction and the phenomenon of the fault, determine the location of the fault, such as the one that has been dropped. For mobile phones, consider mobile phone chip soldering, breakpoints, component shedding, circuit board breaks, etc.; for water inlets, consider power module damage, copper foil and pin rust, corrosion, and disconnection; mobile phones that have been repaired should pay attention to chips Whether it has been moved or exchanged, whether the components are installed incorrectly, etc.

Intuitive method

Through visual inspection after inquiry, some faults can be found. If there is a crack in the casing of the machine that has been dropped, focus on checking the corresponding components on the circuit board to see if there is any drop or disconnection; there are water stains on the main board of the water inlet or even raw embroidery, and there are sundries between the pins; buttons If it is not normal, see if there is oxidation on the button point to cause poor contact; use the blowing method to judge whether the transmission and the microphone are normal.

Voltage method

For a normal mobile phone, the voltage of the corresponding point is a fixed value. Once the mobile phone is damaged, the voltage value at the fault will inevitably change. By detecting whether the voltage value is normal, the fault location will be quickly found. If the voltage is zero somewhere, the power supply There is an open circuit in the circuit; somewhere where the voltage is lower than the normal value, as long as the power supply is normal, it indicates that there is a problem with the load; when measuring the voltage, pay attention to whether it is a continuous DC power supply or a pulsating DC power supply.

Current method

The value displayed by the ammeter on the maintenance power supply is the sum of the current of each unit circuit when the mobile phone is working. The current under different working conditions is basically regular. If the mobile phone fails, the current will inevitably change. The current value can roughly determine the fault location. For example, there is a current of tens of milliamperes when the power is turned on, indicating that the component connected to the positive pole of the power supply is leaking; if the power on current is greater than 500 milliamps, it indicates that the CPU or power supply, power amplifier, and power supply filter Components such as capacitors have breakdown short circuits.

Resistance method

Usually, pay attention to collecting the resistance to the ground of some parts of the mobile phone. Such as power supply reeds, power supply filter capacitors, SIM card holders, chip pads, integrated circuit pins, and other resistance to the ground. When repairing the mobile phone, the fault can be judged according to the resistance value of a certain point to the ground. If the normal resistance from a certain point to the ground is ten kiloohms, and the resistance of the faulty machine at this point is much greater than ten kiloohms or infinity, it means that this point has been disconnected. If the resistance is zero, this point has been short-circuited to the ground; the resistance method is also used to determine whether there is a disconnection between the lines and the quality of the components.

Oriwhiz (Shenzhen DongYe Tengfei Electronics Co., Ltd) is a professional iPhone, iPad, iMac, Mac Book, Xiaomi, Huawei, Samsung, Sony, LG, ASUS repair parts and repair tools supplier. Oriwhiz team aims to provide the best quality cellphone replacement parts and repair tools to all customers. We provide comprehensive solutions for cellphone, digital devices, computer repair shops with powerful and handy cellphone repair packages, repair tools, and repair machines. Browse our product category to select an item you like or contact us for wholesale and distribution issues.