海信电视HZ49A65 卡在开机画面然后自动重启案例分享

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海信HZ49A65 卡在开机画面然后重启
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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
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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
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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)