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例1:故障现象:NV-370录象机,全方式不动作,开启电源开关,数秒钟后电路自动保护,且机内有机械来回摆动的声音。由于电源已经自动保护,可检查中央微处理单元 IC_(6001)的各脚电压,当电路的某一部分不正常时,反映在 IC_(6001)相应脚上的电压也不正常。经查发现(26)、(27)、(28)脚电压异常,分别为0V、4V、4V;而正常值应为4V、4.1V、0V。从系统控制图上看,(26)、(27)、(28)脚分别接方式选择开关 S_1、S_2、S_3,当 S_1、S_2、S_3及
Example 1: Symptom: NV-370 video recorder, the whole does not move, turn on the power switch, the circuit automatically protects after a few seconds, and the machine has mechanical swing back and forth the sound. Since the power supply has been automatically protected, the voltage of each pin of the central microprocessor IC_ (6001) can be checked. When a certain part of the circuit is abnormal, the voltage reflected on the corresponding pin of IC_ (6001) is not normal. The investigation found that (26), (27), (28) voltage anomalies, respectively 0V, 4V, 4V; and normal should be 4V, 4.1V, 0V. From the system control diagram point of view, (26), (27), (28) feet were connected to the mode selector switch S_1, S_2, S_3, S_1, S_2, S_3 and