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我们使用的 11频道1 kW单通道彩色电视发射机是由北京广播器材厂1996年生产的。该机采用了两级电子管功放,前级用FC—620F,末级使用FC—732F。双指针功率表指示放大后的高频调制信号的能量和天馈系统的驻波比。由于两级电子管均工作在高电压,大电流状态,加之本地风沙较多,使得电子管功放级故障率相对较高。现列举三例,供同行参考。 故障现象 1:开机,发射机工作正常,半小时后,双指针功率表指示突然变小(P=0.1,S=1.1),而
We use the 11 channel 1 kW single channel color TV transmitter is produced by the Beijing Broadcasting Equipment Factory in 1996. The machine uses two tube amp, the former with FC-620F, the last use FC-732F. The double-pointer power meter indicates the energy of the amplified high-frequency modulated signal and the standing wave ratio of the antenna-fed system. As the two tubes are working in high voltage, high current conditions, combined with more local sand, making the tube amp-level failure rate is relatively high. Now cite three cases for peer reference. Symptom 1: boot, the transmitter is working properly, half an hour later, the double pointer power meter indicates a sudden decrease (P = 0.1, S = 1.1), and