神雕小鬼 发表于 2015-7-24 13:04

TCL AT2980DB不定时烧行管故障解决方案

故障现象: 三无(灯亮)

机芯: 飞利浦解码OM88**(大屏幕)

机型: 2502D,2516B,2516D,2516DI,2516BI,2580DB,2510G,AT2575,
2575D,2515DZ,2580GI,2580G,2588DB,2511DI,2511D,2511DR,
2511DZ,2575DI,AT2515DZ,AT2590I,AT2590,AT2580D,AT2575D,
AT2575DI,AT2575DZ,AT2575F,AT2588D,AT2539,2939D,2939DR,
2965D,2989D,2913D,2975,2956D,2927D,2915DZ,2988DB,2916D,
2988D,2980G,2980GI,2980DB,2975D,2910G,2910DZ,2910D,2911,
2911D,2911DI,2911DZ,2980D,2988DF,2988DI,2975DI,AT2975D,
AT2980D,AT2980DB,2539D,2539DR,2539DI,3406D,3433D,3433DZ,
3409D,3416,3416D,3416DI,3418D,3416D(F),3438D,3480GI,3488GI,
3460D,3488D,34D106,AT3480DZ,AT3486DI,AT3460D,AT3416D(F),
AT3488DZ,2988G,2988D-F,2911Z,AT2990,AT2915DZ,AT2990I,
AT2975F,AT2975I,AT2988D,AT3480GI,3811DI,2589D,AT2556,AT2988,
AT2988DB,AT2956B,AT2911DZ,AT2915,AT2939,AT2956,AT2975Z,
AT2986Z,AT2575I,AT2586,3488BD,AT3486DZ

检修过程: 2916D不定时烧行管:最初接到此机时行管已经损坏(此机曾被非TCL维修工 修过),重新更换行管图象和伴音都正常,测量电路中电压均正常,观看一段时间后,故障出现:屏幕两边缩小并且行不同步,发出吱吱尖叫声,立即关机。此时用 手模行管散热片,温度明显偏高。依经验怀疑行频偏离所至,于是将晶体及周围小电容逐一更换,接下来继续试机,故障依旧,继续更换OM8838、行输出变压 器、行推动变压器、逆程电容等元件,还是出现故障。最后用加热法对小部件进行逐一加热,当吹到行推动管时故障显现,最后把行推动管(Q401)BF422 更换成C4544,故障排除。

故障板名称: 主板

故障元件位号:Q401

处理措施:更换;Q401(C4544)

图片: 无

请叫我上路逗比 发表于 2015-7-24 17:15

学习了 !{znds14}
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