LAZER MW6617, Service Manual, Page: 14 / 21

5
）
No charger:
The U402
、
U301 & U302 integrate the charger control circuit. When inserting the charging adapter,
CPU detects high level, and start the charging program. To controlled by U301, U302. The R312 is
charge current
Resistance . You can check U402, U301, U302 and R312
6) SIM not work:
Changed the U811,MTK 6166