通电不开机，测试供电发现有3.3V，1.5V等电压均会跳动，这些电压由于都是受控的，程序不正常及DDR到CPU通讯异常也会这样。先查看打印信息发现打印信息反复显示如下： TXL:BL1:1ef924:56431c;FEAT:ADFD718C;POC:1;RCY:0;EMMC:0;READ:0;0.0;CHK:0; TE: 105692 BL2 Built : 18:02:44, Feb 23 2017. txl g3629254 – xiaobo.gu@droid05 set vcck to 1100 mv set vddee to 1000 mv set vddee enable AO_8 to high set vddee enable AO_2 to high DRAM reset… init panel power Board ID = 0 CPU clk: 1200MHz DDR enable rdbi DQS-corr enabled DDR scramble enabled DDR3 chl: Rank0 @ 792MHz – PASS Rank0: 1024MB(auto)-2T-11 DataBus test pass! AddrBus test pass! Set ddr ssc: ppm3000 -s Load fip header from eMMC, src: 0x0000c200, des: 0x01400000, size: 0x00004000 Load bl30 from eMMC, src: 0x00010200, des: 0x01100000, size: 0x0000d600 Load bl31 from eMMC, src: 0x00020200, des: 0x10100000, size: 0x00017400 sd/emmc read data error: ret=16 aml log : SIG CHK : 294 for address 0x10100000 reset… 先怀疑是数据问题，本想先写个数据试试，无意中发现UDPB输出的3.3V不受控，但电压在3V到3.2V在波动，怀疑是UDPB不良，代换后3.3V输出稳定，此时机器已经可以正常开机，反复老化均正常.