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故障现象 一台松下PD92型单放机,重放时图像无彩色,且监视器屏幕出现很多噪波点,以致无法收看,但操作该机其它功能基本无问题。 分析与检修 松下PD92是一种卡拉OK且具有录像功能(需提供外信号)的新机种。从该机现象上看,其它功能正常,仅是重放的图像质量有问题,估计问题出在磁头及其放大器电路中,究其原因主要有以下二方面:(1)视频磁头太脏或有损坏,致使其从磁带上拾取的信号太弱;(2)磁头放大器电路有局部损坏或无视频磁头开关切换控制信号,只有一只磁头信号输出。
Symptoms A Panasonic PD92 single-player, replay images without color, and the monitor screen a lot of noise points, so can not watch, but the operation of other basic functions of the machine no problem. Analysis and Maintenance Panasonic PD92 is a karaoke OK with video capabilities (to be provided outside the signal) of the new models. Phenomenon from the aircraft point of view, the other functions are normal, only the quality of playback problems, the problem is estimated in the head and amplifier circuit, the reasons are mainly the following two aspects: (1) video heads dirty or have Damage, resulting in the signal picked up from the tape is too weak; (2) magnetic head amplifier circuit is partially damaged or no video head switch switching control signal, only a magnetic head signal output.