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二、行扫描电路故障造成的启动困难例9:行启动电压降低,造成行起振困难故障:一台东芝201E3C电视机,启动困难,但启动后工作正常。检修:开机,检查+B1为+114 V(正常),再查行管,发现基极无负压,向前查推动管基极,无15625 Hz的行激励信号,确定为行起振困难。查TA7698(33)脚行启动电压为6V(偏低),再查R419(68 kΩ/3W)行启动电阻,发现其阻值已近100 kΩ,用一新电阻代换后,(33)脚电压正常(8.3V),故障排除(如图8)。
Second, the scanning circuit failure caused by the start-up difficulties Example 9: Line start voltage is reduced, resulting in line start-up difficult failure: a Toshiba 201E3C TV, start difficult, but after starting work properly. Maintenance: boot, check + B1 is +114 V (normal), and then check the line control and found no negative base voltage, forward to promote the base of the tube, no 15625 Hz line excitation signal to determine the line start-up difficulties. Check TA7698 (33) foot start voltage of 6V (low), and then check R419 (68 kΩ / 3W) line start resistance and found that the resistance has been nearly 100 kΩ, replaced with a new resistor, Voltage is normal (8.3V), troubleshooting (Figure 8).