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例1.故障现象 进出碟片、显示均正常,但放入碟片后主轴电机不转。 分析与检修 打开机壳,通电后放入碟片观察,发现碟片不旋转,原因为主电机不转,用万用表测其电源部分供给主轴电机电路的+15V,±12V,±8V均正常,查主轴电源板上的主轴电机驱动电路上的四只晶体三极管也无异常。当用手触摸到激光头安装架下的四只三极管Q108、Q109、Q114、Q115时,发现其中Q108和Q109的温度极高,于是焊下测量发现两只管子b-c结均已击穿。此四管为配对管,必须同时更换四只管子才能正常使用。因无同规格管更换,经查找资料,Q108、Q114可用两只D1758代换、Q109和Q115可用两只B1201代换。经用上述代用三极管更换后,通电装入碟片试
Example 1. Failure phenomenon out of the disc, the display is normal, but after the disc into the spindle motor does not turn. Analysis and maintenance Open the case, put the disc into the power after the observation and found that the disc does not rotate, because the main motor does not turn, with a multimeter to measure the power supply part of the spindle motor circuit +15 V, ± 12V, ± 8V are normal, Check the spindle power supply board on the spindle motor drive circuit of the four transistor is no exception. When touches the four transistors Q108, Q109, Q114, Q115 under the laser head mounting frame, it is found that the temperature of Q108 and Q109 is extremely high. Therefore, the two tubes b-c junctions have been punctured by the welding measurement. The four tubes for the paired tube, you must also replace the four tubes to normal use. Because no specification tube replacement, the search for information, Q108, Q114 available two D1758 substitutions, Q109 and Q115 available two B1201 substitution. Replacement by the use of the above transistor, the power into the disc test