Reason: The phone RF circuit and CPU are in high frequency operation. It consumes much power consumption, and this will produce certain amount of heat. Also, a high current will going through the charging circuit when charging the phone, there will be a certain amount of heat, which is a normal phenomenon.

Solution: Do not play your phone while charging the mobile Internet or play the large-scale game, and avoid prolonged call, video play.

Reason:

(1) To much program running background

(2) The screen brightness is high.

(3) Bluetooth, GPS, WIFI connection are always running.

(4) Using the phone while charging it.

Solution:

(1) Shut down the program running in the background to reduce unnecessary consumption.

(2) Adjust the screen brightness

(3) Turn off Bluetooth and GPS positioning system

(4) Charge the phone every day, do not use the phone while charging it.

Reason:

(1) Headset is on.

(2) The microphone is broken.

Solution:

(1) Turn off headset mode. Some phones have headset mode, it will turn off the microphone. So the one can not hear the sound.

(2) Water damaged the phone. Turn to after-sales center for replacement.

Reason:

(1) SIM card is not placed properly.

(2) SIM card holder is damaged. (3) SIM card is too old or damaged.

Solution:

(1) Check if the SIM card is placed correctly.

(2) If SIM card holder is damaged, go to the Customer Service Center for replacement. (3) Rub the SIM card with a pencil eraser or have the SIM card exchanged.