User's Manual

Repair steps:
1. Check if keypad and DOME are damaged, the assembly OK ,and foreign matter exist, etc;
2. Check if the surrounding components (mainly varistors) on the main board are damaged and
have soldering issues, etc;
3. Replace with new keypad or side key, and verify again;
4. If you still have not found the problem, then check whether the U1 chip has soldering or
performance problems or not.
5.4. Microphone function abnormity
Repair steps: