Simply teach you how to deal with cell phone malfunctions

Basic skills for mobile phone repair This section mainly introduces some basic knowledge of mobile phone repair, the general scope of faults and general skills for mobile phone repair, so that Internet users can quickly repair mobile phones with common faults.

1. After automatic power-on and adding the battery, it will be in the power-on state without pressing the on/off key. It is mainly caused by the short circuit of the on/off key to ground or the short circuit of other components on the boot line to ground. Most of the time, this fault can be solved by removing the phone board, soaking it in alcohol and cleaning it.

2. Automatic shutdown (automatic power off) 1. Automatically shuts down when vibrating. This is mainly caused by poor contact between the battery and the battery contacts. 2. As long as you don't press the keyboard to turn off the phone, the phone will not shut down and the phone will automatically shut down when certain keys are pressed. This is mainly caused by weak soldering of the CPU and memory. Strengthening the welding of the memory, CPU and memory can generally solve the problem. 3. Transmit shutdown: The mobile phone automatically shuts down as soon as the transmit button is pressed. This is mainly caused by a fault in the power amplifier. This fault is usually caused by the power supply IC (or power amplifier control).

3. Emit weak electricity and emit signals 1. When the mobile phone emitting weak electricity is in the standby state, it does not show weak electricity. When making a call, or after making several calls, it immediately displays weak electricity, and a low battery alarm occurs. This phenomenon is first caused by dirty or poor contact between the battery and contact pad interface; secondly caused by poor contact between the battery contact pad and the mobile phone circuit board; and thirdly caused by damage to the power amplifier itself. 2. The signal is lost when the mobile phone is in standby mode. The signal is normal, but the signal is lost as soon as the mobile phone transmits. This phenomenon is caused by a fault caused by weak soldering or damage to the mobile phone's power amplifier.

4. Electricity leakage Cell phone leakage is a difficult fault to repair. First, determine whether the power supply part and the power switch tube are burned out and cause a short circuit. Secondly, determine whether the power amplifier is damaged. Secondly, if the leakage current is not too large, power on the phone for 1 to 2 minutes and then use the back of your hand to feel which part of the component is extremely hot. This component must be broken and should be replaced. If the above method still does not solve the fault, the only option is to check whether there are resistors, capacitors or printed circuit short circuits in the circuit.

5. Failure to access the network and failure to access the network can be divided into two situations: no access to the network with signal and no access to the network without signal. Currently on the market, Ericsson series and Samsung series mobile phones will display the signal strength value as long as the receiving channel is good, regardless of whether there is a transmitted signal. Other series of mobile phones must wait until the mobile phone enters the network before displaying the signal strength value. For other series of mobile phones, when judging the scope of the fault, insert the SIM card into the mobile phone, adjust the menu, and use the manual search method to find the network. At this time, the network can be found, which proves that the receiving channel is good, and it is caused by the failure of the transmitting channel. If the network cannot be found using the menu method, it means that the receiving channel is faulty. Repair the receiving channel first.

6. The signal is unstable (dropped signal) due to weak soldering of the receiving channel components (mobile phones that have been dropped are prone to this failure)

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