机型：L55P2-UD 机芯T968
故障现象：不开机
维修与分析：网点送修主板，通电试机打印信息就这样： GXTVBB:Fixed PLL lock failed BL1:ee57c+:7a1241;FEAT:EDFD718C;POC:3;RCY:0;EMMC:0;READ:0;CHK:0; no sdio debug board detected TE: 300653 BL2 Built : 16:14:20, Sep 30 2016. gxtvbb gfdb57f2 – xiaobo.gu@droid05 set vcck to 1100 mv set vddee to 1100 mv init panel power Board ID = 1 SYS PLL lock check 1 SYS PLL lock check 2 SYS PLL lock check 3 SYS PLL lock check 4 SYS PLL lock check 5 SYS PLL lock check 6 SYS PLL lock check 7 SYS PLL lock check 8 SYS PLL lock check 9 SYS PLL lock check 10 SYS PLL lock failed! reset…一直重复打印，首先检查主板上各个稳压供电，发现UD016输出对地短路，拆UD016下来还是对地短路，检查外围电路发现C572短路，更换后故障排除！
