论文部分内容阅读
故障一:TCL-D302型VCD 光盘不转,不能重放。 分析与检修:引起VCD不能重放的原因较多,首先检查光头物镜表面,没有灰尘和污物明亮如新;再通电检查光头的工作状态,发现光头没有径向的循迹动作;然后放入光盘作进一步检查,光盘不转动,造成不能重放。由机芯结构可知,光头的径向循迹和光盘的转动是分别由进给电机和主轴电机带动的,这两个电机同时损坏的可能性不大。通过电路原理分析,发现进给电机和主轴电机的转动都是受驱动集成块U3(TDA7073)控制的。检查U3的工作情况,发现⑤脚没有+9V的供电电压,说明U3没有工作。U3的+9V电压是经电源部分通过变压器降压,再由整流、稳压后获得的。沿着线路进行排查,当检查至供电电路上的限流电阻R822(2.2Ω)时,发现它已断路。拆下换上一只新的R822后,试机可以重放,恢复正
Fault one: TCL-D302 VCD disc does not turn, can not be replayed. Analysis and Maintenance: Cause VCD can not be replayed for many reasons, first check the bald objective lens surface, no dust and dirt as bright as new; and then check the working state of the bald power and found no radial head tracking action; and then into CD-ROM for further examination, the CD does not rotate, resulting in can not replay. It can be known from the movement structure that the radial tracking of the optical head and the rotation of the optical disk are respectively driven by the feed motor and the spindle motor, and the possibility of the two motors being damaged at the same time is not great. Through the circuit theory analysis, found that the feed motor and spindle motor rotation are driven by the drive manifold U3 (TDA7073) control. Check the working condition of U3 and found that there is no + 9V power supply voltage feet, indicating that U3 did not work. U3 +9 V voltage is the power part of the step-down transformer, and then by rectification, obtained after the regulator. Follow the line to check, when checking to the power supply circuit current limiting resistor R822 (2.2Ω), it was found that it has been open. After removing a new R822, the test machine can replay, restore positive