According to the fault performance analysis of only one bright line on the screen, the fault may be in the excitation oscillation circuit or the excitation output circuit. The airport scanning output circuit is composed of integrated circuit IC45l(AN552 1), and its working voltage (+25v) is directly provided by switching power supply. The field frequency pulse is formed by dividing the oscillation frequency of the external crystal oscillator at the pin IC60l (37) by its internal count. Foot output (50Hz or 60Hz). Because when the remote control is turned off, the red light can light up and the screen has a grating (horizontal bright line), indicating that the fault lies in the standby circuit. During maintenance, the voltage at pin ⑤ of S85 plug-in was measured and found to be 0V, and then the voltage at both ends of C83 1 was 27V, which was within the normal range. Check the resistor R84 1 and find that the resistor has been damaged by an open circuit. Replace R84 1, start the machine, and observe that the grating returns to normal, but it cannot be closed remotely. Press the power-off button of the remote controller, and measure the base voltage of Q802 to be 0.7V and the collector voltage to be l2.8v It is suspected that Q802 has been damaged. Try to replace Q802 with a new tube, start the test, and the TV set will work normally, and troubleshoot. I hope I can help you! ! !