康佳D系列中小屏幕彩电待机与保护电路检修(下)
整理日期:2008-1-6 1:11:13 资料编辑: 点击次数:
| 编号与名称 | 引脚 | 开机电压V | 待机电压V | 开机电阻KΩ | 待机电阻KΩ |
| V901 | c | 295 | 305 | 17.2 | 32.5 |
| 2SD1710 | b | -2.7 | -1.1 | 6.1 | 7.9 |
| e | 0.3 | 0.01 | 0 | 0 | |
| V902 | c | -2.7 | -1.1 | 6.1 | 7.9 |
| 2SC3087 | b | -4.6 | -0.7 | ∞ | 7.6 |
| e | -4.6 | -1.3 | ∞ | 5.6 | |
| V903 | c | -2.7 | -1.1 | 6.1 | 7.9 |
| 2SD400F | b | -3.4 | -0.7 | ∞ | 11.2 |
| e | 0 | 0 | 0 | 0 | |
| V904 | c | -4.7 | -0.7 | ∞ | 7.6 |
| 2SA1015 | b | -0.6 | 0 | 8.4 | 9.6 |
| e | 0 | 0 | 0 | 0 | |
| V905 | c | -0.6 | 0 | 8.4 | 9.6 |
| 2SC1815 | b | -30.2 | -19.4 | 17.2 | 8.3 |
| e | -34.2 | -16.2 | 9.6 | 17.2 | |
| V906 | c | 25.2 | 0 | 10.2 | 15.2 |
| 2SA1015 | b | 24.4 | 14.4 | 12.2 | 62 |
| e | 25.2 | 5 | 5 | 33 | |
| V907 | c | 0 | 5 | ∞ | 17.8 |
| 2SA1015 | b | 5 | 4.5 | 7.1 | 7.3 |
| e | 5 | 5 | 3.3 | 3.5 | |
| V908 | c | 28.4 | 26.2 | 72 | ∞ |
| 2SC1815 | b | 0.3 | 5.4 | 155 | 155 |
| e | 0.1 | 4.5 | 12.2 | 1000 | |
| V610 | c | 0 | 14.2 | 14.2 | 95 |
| 2SC1815 | b | 0.7 | 0.1 | 16.2 | 11.2 |
| e | 0 | 0 | 0 | 0 | |
| V471 | c | 0 | 0 | ∞ | 11.6 |
| 2SA1015 | b | 12.2 | 0.5 | 6.6 | 6.3 |
| e | 12.2 | 0.5 | 1 | 1 | |
| V473 | c | 4 | 0 | 6.7 | 6.8 |
| 2SC1815 | b | 0 | 0 | 7.4 | 7.4 |
| e | 0 | 0 | 0 | 0 | |
| V474 | c | 4.5 | 4.4 | 11.2 | 17.2 |
| 2SC1815 | b | 0 | 0 | 7.4 | 7.4 |
| e | 0 | 0 | 0 | 0 | |
| N901 | 1 | 30.2 | 23 | 10.2 | 155 |
| TLP621 | 2 | 29.7 | 22 | 52 | ∞ |
| 3 | -4.5 | -0.01 | ∞ | 7.1 | |
| 4 | 0 | 0 | 0 | 0 | |
| N903 | 1 | 0 | 1.2 | ∞ | 17.8 |
| TLP621 | 2 | 0 | 0 | 0 | 0 |
| 3 | -2 | 0.03 | ∞ | ∞ | |
| 4 | 0 | 0 | 0 | 0 |
注:所测数据均是用MF-47指针式万用表测得,电阻用R×1 kΩ档测得。测试开关变压器初级电路元件以C901负极为热地端,开关变压器次级以B+1滤波电容器C922负极为冷地端,测量时千万不能将接地端搞错。
2.解除保护,观察故障现象
解除保护时,必须确保开关电源输出电压正常和行扫描电路无明显短路故障,避免解除保护后造成故障扩大,损坏其他元件。可采用断开行输出电路供电,接假负载的方法,解除保护,确定开关电源输出电压正常后,再恢复行输出电路。
(1)从故障检测电路采取措施,解除保护状态:逐个断开各个保护取样电路与可控硅VS472控制极的连接:B+1过压检测电路,断开R475;“X射线”过高检测电路断开VD474;显像管束电流过流检测电路,断开VD473,并重新启动电视机试之。如果断开那个保护电路与可控硅VS472控制极的连接重新开机后,开关电源退出保护状态,则是该保护电路动作,触发可控硅,进入保护状态。
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