海信HZ49A65 卡在开机画面然后重启 机芯方案:Hi3751V5510 故障原因分析:卡在开机画面重启,首先测量电源管理电路DC-DC,LDO有无异常,如果无异常下一步通过打印信息进行故障判断, 检修过程:卡在开机画面重启,首先测量电源管理电路DC-DC,LDO未发现异常, 连接工装部分打印信息如下: [ 1.857896] init: couldn't write 1632 to /dev/cpuset/foreground/tasks: No such file or directory [ 2.054082] init: couldn't write 1606 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory [ 2.072091] init: couldn't write 1612 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory [ 2.086197] init: couldn't write 1610 to /dev/cpuset/system-background/tasks: No such file or directory [ 3.748736] init: Service toltech does not have a SELinux domain defined. [ 5.721492] pgd = ffffffc073728000 [ 5.724883] [0000009c] *pgd=0000000000000000, *pud=0000000000000000 [ 8.811371] init: couldn't write 1991 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory [ 8.814189] init: couldn't write 1992 to /dev/stune/foreground/tasks: No such file or directory [ 8.839500] init: cannot find '/system/bin/teecd' (No such file or directory), disabling 'teecd' [ 8.908066] init: cannot setexeccon('u:r:logwrapper:s0'): Invalid argument <IAMREADY> 更换N60的DDR K4A8G165WB-BCRC 后故障排除。 故障主板号:RSAG7.820.7941 故障元件:K4A8G165WB-BCRC 海信HZ55A52 白屏 机芯方案:MSD648 故障现象:白屏 故障原因分析:Ⅴcom电压是液晶分子偏转的参考电压,其出问题将使得液晶分子偏转不正常造成白屏 检修过程:电视白屏说明液晶旋转控制出问题了,测量ⅤGH、VGL、Vcom电压,发现Ⅴcom电压为0,由于Vcom电压是由N25(G1632)提供,测其外围无短路,将N25换之,故障排除。 故障板号:RSAG7.820.8802 故障元件:N25(G1632) |