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问:手机插卡后开机显示“请插入卡”,如何维修? 答:开机,SIM卡座各触点均能测到脉冲信号,说明SIM卡的各条通信线路无开路,再查R128、R124、R125均正常,查V104模块,发现其中一个二极管已坏,此管是对VSIM电压进行稳压的,换V104后,故障排除。问:手机插卡开机后,显示卡上没有网络及场强显示,如何维修? 答:加电后,测C532、C533的RXI、RXQ,均无,查N600⑥脚有5V输入,且①脚有2.8V的控制方波信号(正常),但④脚电压只有2.0V(正常应为2.75V),换N600后,一切正常。
Q: After powering on the card, please insert the card. How to repair? A: After power on, all the contacts of the SIM card socket can detect the pulse signal, indicating that the communication lines of the SIM card are not open, and then check the R128 and R124 , R125 are normal, check V104 module and found that one of the diodes has been bad, this tube is the VSIM voltage regulator, for V104, troubleshooting. Q: After powering on the phone card, there is no network and field strength on the display card. How to repair? A: After power-on, measure the RXI and RXQ of C532 and C533, none of them. 2.8V square wave control signal (normal), but ④ pin voltage only 2.0V (normal should be 2.75V), for N600, everything is normal.