测整机高压供电电路C2对地+305V电压。正常;测低压供电电路Q6电源调整管e极对地电压为+18V。正常;测u3(LM7805)OUT对地电压+5V,正常。测同步电压比较器(7)脚同相输入端对地电压为+2v,偏低(正常为+4.2V)。用R×100挡测LM339发现(7)脚同相输入端旁路电容器C20(104)漏电,更换C20后整机恢复正常。 |
|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, 2025-5-29 13:32 , Processed in 0.110288 second(s), 18 queries .
Powered by Discuz! X3.5
© 2001-2025 Discuz! Team.