Search network manually is no signal, no Internet access, it is judged to be receiving circuit caused by poor. First, replace the antenna switch FL100 U50, filters, RF IC U150, still without Internet access. At this time to set up their phones in RX60 channel, measured c152 CP-Rx is 1. 5 v, and significantly lower (normal is about 2~3 v), since CP-RX is inside the CPU which is output phase, phase power output by the power supply Ic e ⑩ feet provided by RF-5, V-REG, C827 measured on only 4 next to the CPU. 2 v, VBOOST suspects the above step-up power supply 5. 6 v low measured C921A is only 4. 2 v, if that is the case, replace the L92 boost inductor or 4. 2 V。 According to repair P2K mobile phone experience, 5. 6 v booster is low, common are power supply IC badness, so after replacing the power supply IC, troubleshooting.B3kservice manual download site