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摩托罗拉掌中宝系列手机在市场上有相当大的拥有量,该系列手机出现不开机的情况比较多,此故障具有较强的代表性。由于其开机流程比较复杂且缺乏相关的技术资料,给检修带来了较大的困难。下面将对该系列手机的开机流程作简单的分析(其开机流程图见本期“资料汇编”栏)。加电不开机时,电池电压通过电子开关送到U900第(25)、(37)脚,经内部电路转换后从其触发端第(24)脚输出3V的触发电压,手机进入开机准备状态。当按下开机键
Motorola handheld treasure series phones in the market have a considerable amount of ownership, the series appeared more mobile phone does not boot more, this failure is more representative. Due to its boot process is more complicated and the lack of relevant technical information, maintenance has brought greater difficulties. The following will be a brief analysis of the series of mobile phone boot process (the boot flow chart see the current “compilation” column). When the power is turned on, the battery voltage is sent to the U900’s (25), (37) via the electronic switch. After the internal circuit is switched, the trigger voltage of 3V is output from its trigger terminal (24). When you press the power button