There are many reasons why the mobile phone has power but cannot be turned on! Here are some details for you, I hope they can help you!

1. Check if the power-on line is abnormal: Use an external power supply to power the mobile phone, and use an electrical connection meter to check if there is any change in the display. If there is no change, it is likely that the power-on line is broken or the power-on button is in contact. bad.

2. The battery power supply circuit is abnormal: Use the external interface to power the mobile phone and see if it returns to normal when it is turned on. If it is normal, it is determined that the mobile phone's power supply circuit is abnormal.

3. The IC of the mobile phone power supply is abnormal: compare the circuit schematic diagram and conduct a test on the test points of the peripheral circuit of the power supply IC to see if the test value is normal.

4. The system clock and reset of the mobile phone are abnormal: You can use a dual oscilloscope to detect the CPU power supply of the mobile phone and check whether the waveform diagram during reset is correct.

5. Logic circuit problems: This is a problem in the circuit board of the mobile phone. This problem can generally be solved by repair welding.

6. Software conflict: The installed software is inconsistent with the system of the mobile phone, which may also cause the mobile phone to fail to turn on. You can connect the mobile phone to the computer to delete the program.

7. If it is a copycat mobile phone, then I guess it cannot be turned on because the chip inside is burned, or some small parts inside are loose. However, this situation will only occur if you drop it. If the chip is burned, it may be that you have charged it for too long and burned the chip. If the battery has power, it is in these aspects. If it is a famous brand mobile phone, such as Nokia, Motorola...this situation occurs. It's very rare, unless it's man-made. If it's a brand-name smartphone and it's not used improperly, it's a software problem. It may be a system crash, or the software is damaged because the phone is poisoned. Generally, you can only go to a repair shop. However, I think the most likely cause is static electricity. It is recommended that you don’t open and repair it yourself, but go to a repair shop!