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例1 故障现象:一台YONGDA(永达)牌K—333型VCD机,碟片不能出仓,能够正常播放。分析检修:打开机壳,用万用表检查Q_(901)、Q_(902)和出入仓电机均正常;直观检查其仓门也无异常。接着通电测出仓供电稳压电路Q_(910)(2SD882)集电极电压为11V,正常;测基极电压6.5V,正常;测发射极电压为0V。关机拆下Q_(910),用万用表测得其b—e极正反向电阻为无穷大,确定为Q_(910)损坏。由于无该三极管更换,于是用7805或7806三端稳压器代替稳压
Example 1 Symptom: A YONGDA card K-333 VCD disc, the disc can not be released, can play normally. Analysis and Maintenance: Open the case, with a multimeter check Q_ (901), Q_ (902) and the warehouse motor are normal; visual inspection of the warehouse door is no exception. Then energized to determine the power supply regulator circuit Q_ (910) (2SD882) collector voltage of 11V, normal; base voltage 6.5V, normal; measured emitter voltage is 0V. Shut down to remove Q_ (910), measured with a multimeter its b-e pole positive and negative resistance to infinity, identified as Q_ (910) damage. As the transistor is not replaced, then use 7805 or 7806 three-terminal regulator instead of regulation