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该机为转修机,原故障是:图像上有条纹干扰,别人修了三天,换过LA7680(N101)、LA7837(N451)等好多元件,包括偏转都拆下来检查,后来才换到180V供电滤波电容后,条纹干扰没有了,却出现了场不同步现象。他先后又换了晶体G421(500kHz)、C401(2.2μF/50V)等元件,都没有好转。由于此机没有像TA7698场同步调节,而是通过N101(LA7680)(25)脚外接500kHz晶体产生频率为500kHz的振荡信号,经LA7680内部32分频,得到15625Hz行频信号;同一个500kHz的振荡信号经水平分频器中的16分频器分频后,得到31.35kHz信号,再经垂直分频器进行625分频后,形成50Hz场频信号。
The machine is a turn-over machine, the original fault is: there are stripes on the image interference, others for three days, changed LA7680 (N101), LA7837 (N451) and many other components, including the deflection are removed to check before switching to 180V power supply Filter capacitor, the fringe interference is gone, but there is a phenomenon of field does not sync. He has changed the crystal G421 (500kHz), C401 (2.2μF / 50V) and other components, have not improved. Because this machine does not like TA7698 field synchronous regulation, but through the N101 (LA7680) (25) external 500kHz crystal oscillator frequency 500kHz signal generated by the LA7680 internal division 32, 15625Hz line frequency signal; the same 500kHz oscillation After the signal is divided by a 16-divider in the horizontal divider, a signal of 31.35 kHz is obtained, and then divided by 625 by a vertical divider to form a 50-Hz field-frequency signal.