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例1 海信牌 SR5468A 型彩电,伴音失真故障伴音中夹杂有强烈的蜂音。一般而言,蜂音干扰故障原因在于调频鉴频中心频率或进入鉴频器的伴音中频信号偏移,因此故障的检修范围应在 N101②、(45) 脚。参照图1。检修中试图测一下 N101②脚直流电压,当表笔一碰到②脚时,故障立即消失,伴音变得清晰,完全正常。反复振动线路板故障也不再重现,当然测各点电压均正常。由于没有查出问题原因,还不能认为修好,通电放在一边观察,但一直不出现问题。或许②脚外围有异常?逐一拆下②脚外围元件测量都正
Example 1 Hisense brand SR5468A color TV, sound distortion fault sound mixed with a strong buzz. In general, the cause of the buzzer interference is that the frequency of the frequency center or the audio intermediate frequency signal of the frequency discriminator is shifted. Therefore, the troubleshooting scope of the buzzer should be at N101② and (45). Refer to Figure 1. Overhaul try to measure N101 ② foot DC voltage, when a touch pen ② feet, the fault disappears immediately, the sound becomes clear, completely normal. Repeated vibration circuit board failure is no longer reproducible, of course, test the voltage at all points are normal. Because it did not identify the cause of the problem, it can not be considered repaired, while the power is on the sidelines, but no problem has been found. Perhaps ② peripheral abnormalities? Remove one by one ② feet peripheral components are measured