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故障现象:一台加装遥控系统的东芝TA两片机,L、H波段接收正常,U段接收灵敏度低,雪花较大。分析与检修:首先确定该电视机的输入电视信号是否正常,该用户有两台电视机,另一台收看正常,将故障电视机接上收看正常的天线信号,故障依旧,判断是电视机内部电路故障。开机检查与灵敏度有关的高频“MB”、“AGC”、“AFT”电压正常,考虑到L、H波段接收正常,判断故障在高频头内部电路。更换一个新的增补高频头后,却出现了新的故障,L、U波段接收正常,而H波段接收灵敏度下降,雪花大并伴有网纹干扰。怀疑新增补高频头有故障,但将该高频头拆下换到其他电视机上却收视正常,看来电
Symptom: A Toshiba TA two-chip remote control system installed, L, H band to receive normal, U-segment receiver sensitivity is low, larger snowflakes. Analysis and Overhaul: First determine whether the television’s input TV signal is normal, the user has two TV sets, the other watch normal, the faulty TV connected to watch the normal antenna signal, the fault is still to determine the internal TV circuit failure. Boot check and sensitivity related to high-frequency “MB”, “AGC”, “AFT” voltage is normal, taking into account the L, H band to receive normal, to determine the fault in the tuner internal circuit. Replacement of a new patch tuner, there has been a new failure, L, U band to receive the normal, and H-band receiver sensitivity decreased, snowflake and accompanied by moire interference. Suspected additional patch tuner failure, but will remove the tuner to other TV sets but ratings normal, it seems