海信TLM32V66A,机芯MST740KULS,4204主板:热机后,伴音过轻。【故障】出现时测N16TDA7266SA伴音功放供电3,13脚12V,正常。6脚MUTE无电压(据原理分析,此脚正常时为12V).测静音管V29(3904为NPN管)B脚为0.65V(正常时0V),再测静音控制二极管VD60输入端电压0V,正常;再测开关机三极管V28(3906PNP管)输出脚C极有5V变化电压(正常为0V).经更换V28,用吹风机加热,声音始终正常 |
|Archiver|手机版|家电维修论坛
( 蜀ICP备19011473号-4 川公网安备51102502000164号 )
GMT+8, 2025-4-30 14:42 , Processed in 0.149514 second(s), 23 queries .
Powered by Discuz! X3.5
© 2001-2025 Discuz! Team.