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故障现象 开机后伴音正常,但屏幕中间只有一条水平亮线。 分析与检修 屏幕中间水平一条亮线这一故障现象,是垂直偏转线圈中没有扫描电流引起的,由此说明问题出在场扫描电路。在西湖新生代2100C彩电中,由N301(TA8445K)集成电路来完成场扫描的全部功能。相关电路如图所示。由N210(TA8690)的(30)脚输出场频激励脉冲经过耦合电阻R302至N301的②脚,触发N301内部单稳态电路产生一定宽度的场频脉冲。场频脉冲在N301内部经处理后给⑤脚外接的锯齿波形成电容C302充电,形成锯齿波电压。锯齿波电压再经N301内部处理、放
Symptom After the boot sound with normal, but only a horizontal bright line in the middle of the screen. Analyze and troubleshoot the phenomenon of a bright line in the middle of the screen caused by no scanning current in the vertical deflection coil, thus indicating that the problem is the presence of the scanning circuit. In the West Lake Cenozoic 2100C color TV, the N301 (TA8445K) integrated circuit to complete the full field scanning functions. Related circuit as shown. Output by the N210 (TA8690) (30) feet field excitation pulse coupling resistor R302 to N301 ② feet, trigger N301 internal monostable circuit to produce a certain width of the field frequency pulse. Field pulse after N301 internal processing to the ⑤ foot external sawtooth wave capacitor C302 charge to form a sawtooth voltage. Sawtooth wave voltage and then by N301 internal processing, put