接修一张TCL售后的板子，手上刚好有同型号的板子就先给他解决用户问题了，今天有时间拿出来修下，有几个我之前没有遇到的问题所以写了篇笔记。
主板板号：40-T96804-MAB2HG
电视机芯：T968A1
芯片方案：amlogic T968-H
故障现象：指示灯亮不开机
客户拿来时候已经在别的地方修过，他重新升过系统，但是故障没有变化。别人已经判了死刑了，对这种二手故障机我修的时候习惯性先看他动了哪里，主芯片应该是补焊过。别的没发现动过哪里。
通电之前测了几个主要的供电点没有短路，连接爱修网的RT809H通电看有没有打印信息，有打印心中暗喜：
从打印信息看应该是主芯片没有工作，但是这个板子修过很多块都是U800坏引起的，也是本着先易后难的原则，换了一个U800，写入备份，再装回看打印信息，结果和上面的一样。测量复位发现只有2.5v，明显不对，找到后仔细观察复位电路，被动过，R814电阻被去掉了。于是找图纸看看多大的，图纸标注为100Ω，R813、R816、R853、R803，几个阻值都和图纸的不一样，因为我的基础比较差，所以都按图纸上的换了，换后复位3.3v正常了，但是仍然没有打印信息。
接下来开始检查各路供电及其对地压降、复位和时钟，未发现明显异常的地方，于是换主芯片，这就让我开始了苦逼的换芯之路，连换3片都没有打印，第4片打印信息出来了:
老师指导说数据总线正常，地址总线的问题，这样的指导让我省了很多的测量工作，这个芯片架构的DDR1在芯片的顶部两片DDR。经测量发现R669、R671压降明显不对，拆卸DDR测量还是这两个地方不对，仍然是CPU 的问题，最后换了一片，打印信息正常了，图像也出来了。
打印信息如下：
GXTVBB:BL1:ee57c+:7a1241;FEAT:EDFD718C;POC:3;RCY:0;EMMC:0;READ:0;CHK:0;
no sdio debug board detected
TE: 67010
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
CPU clk: 1536MHz
CLK81: 167MHz
HHI_MPLL_CNTL: 0xc00006fa
DDR channel: DDR0+1 two channel @ 720MHz
DQS-corr enabled
DDR0: 1024MB-2T-11
DDR1: 512MB-2T-11
DataBus test pass!
AddrBus test pass!
-s
Load fip header from eMMC, src: 0x0000c000, des: 0x01400000, size: 0x00004000
Load bl30 from eMMC, src: 0x00010000, des: 0x01000000, size: 0x000083c0
Sending bl30.................................OK.
Run bl30...
Load bl301 from eMMC, src: 0x0001c000, des: 0x01000000, size: 0x00001af0
Wait bl30...Done
Sending bl301.......OK.
Run bl301...
Load bl31 [rom eMMC, src: 0x00020000, des: 0x10100000, size: 0x00013140
Image: gxtvb_v1.1.3079-626bd02 2016-04-15 13:44:07 jianxin.pan@droid06]
efuse_setup() 221: OPS=0x12
efuse_setup(Load bl33 from eMMC, src: 0x00034000, des: 0x01000000, size: 0x0009a010
) 249: HDCP=0x0c REG32(SEC_AO_SEC_SD_CFG9)=0x00000007
bl30: check_permit, count is 1
bl30: check_permit: ok!
chipid: ef be ad de d f0 ad ba ef be ad de not ES chip
[0.193152 Inits done]
secure task start!
high task start!
low task start!
low task NOTICE: BL3-1: v1.0(debug):db24c1e
NOTICE: BL3-1: Built : 21:16:03, Mar 10 2016
INFO: BL3-1: Initializing runtime services
WARNING: No OPTEE provided by BL2 boot loader
ERROR: Error initializing runtime service opteed_fast
INFO: BL3-1: Preparing for EL3 exit to normal world
INFO: BL3-1: Next image address = 0x1000000
INFO: BL3-1: Next image spsr = 0x3c9
U-Boot 2015.01-gfbd2a78 (Nov 01 2016 - 19:10:33)
DRAM: 1.5 GiB
Relocation Offset is: 56ed9000
low task comd=0x00060100
into process_low_task
into LOW_TASK_Upllow task comd=0x00000110
into process_low_task
LED timer...
INFO: PSCI Affinity Map:
INFO: AffInst: Level 0, MPID 0x0, State ON
INFO: AffInst: Level 0, MPID 0x1, State OFF
INFO: AffInst: Level 0, MPID 0x2, State OFF
INFO: AffInst: Level 0, MPID 0x3, State OFF
bl31 reboot reason: 0x101
bl31 reboot reason: 0x101
ERprc08915c0000000000set vddee to 0x044cmv
exit_reason:0x02
GXTVBB:BL1:ee57c+:7a1241;FEAT:EDFD718C;POC:3;RCY:0;EMMC:0;READ:0;CHK:0;
no sdio debug board detected
TE: 53524
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
CPU clk: 1536MHz
CLK81: 167MHz
HHI_MPLL_CNTL: 0xc00006fa
DDR channel: DDR0+1 two channel @ 720MHz
DQS-corr enabled
DDR0: 1024MB-2T-11
DDR1: 512MB-2T-11
DataBus test pass!
AddrBus test pass!
-s
Load fip header from eMMC, src: 0x0000c000, des: 0x01400000, size: 0x00004000
Load bl30 from eMMC, src: 0x00010000, des: 0x01000000, size: 0x000083c0
Sending bl30.................................OK.
Run bl30...
Load bl301 from eMMC, src: 0x0001c000, des: 0x01000000, size: 0x00001af0
Wait bl30...Done
Sending bl301.......OK.
Run bl301...
Load bl31[from eMMC, src: 0x00020000, des: 0x10100000, size: 0x00013140
Image: gxtvb_v1.1.3079-626bd02 2016-04-15 13:44:07 jianxin.pan@droid06]
efuse_setup() 221: OPS=0x12
efuse_setup(Load bl33 from eMMC, src: 0x00034000, des: 0x01000000, size: 0x0009a010
) 249: HDCP=0x0c REG32(SEC_AO_SEC_SD_CFG9)=0x00000007
bl30: check_permit, count is 1
bl30: check_permit: ok!
chipid: ef be ad de d f0 ad ba ef be ad de not ES chip
[0.179677 Inits done]
secure task start!
high task start!
low task start!
low task NOTICE: BL3-1: v1.0(debug):db24c1e
NOTICE: BL3-1: Built : 21:16:03, Mar 10 2016
INFO: BL3-1: Initializing runtime services
WARNING: No OPTEE provided by BL2 boot loader
ERROR: Error initializing runtime service opteed_fast
INFO: BL3-1: Preparing for EL3 exit to normal world
INFO: BL3-1: Next image address = 0x1000000
INFO: BL3-1: Next image spsr = 0x3c9
U-Boot 2015.01-gfbd2a78 (Nov 01 2016 - 19:10:33)
DRAM: 1.5 GiB
Relocation Offset is: 56ed9000
low task comd=0x00060100
into process_low_task
into LOW_TASK_Unllow task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
low task comd=0x00000110
into process_low_task
LED timer...
uboot time: 3447547 us
[ 0.000000@0] Initializing cgroup subsys cpu
[ 0.000000@0] Initializing cgroup subsys cpuacct
[ 0.000000@0] Linux version 3.14.29-svn3465 (liushi@npi2) (gcc version 4.9.2 20140904 (prerelease) (crosstool-NG MStar-1.13.1-4.9-2015.04 - MStar GCC 4.9-2015.04) ) #1 SMP PREEMPT Fri Jul 21 13:08:53 CST 2017
[ 0.000000@0] CPU: AArch64 Processor [410fd034] revision 4
[ 0.000000@0] no prop version_code
[ 0.000000@0] bootconsole [earlycon0] enabled
low task comd=0x00000003
into process_low_task
[ 0.426947@0] pinmux-gxtvbb c1109880.pinmux: pin GPIOH_7 already requested by c1108d80.spicc; cannot claim for wifi.37
[ 0.432129@0] pinmux-gxtvbb c1109880.pinmux: pin-42 (wifi.37) status -22
[ 0.438893@0] pinmux-gxtvbb c1109880.pinmux: could not request pin 42 (GPIOH_7) from group wifi_32k_pins on device c1109880.pinmux
[ 0.450769@0] aml_wifi wifi.37: Error applying setting, reverse things back
[ 0.697772@0] mtdoops: mtd device (mtddev=name/number) must be supplied
至此本机修复完毕，芯片问题很糟心。
报名联系方式
国内
电话：020-28667686（潘老师）
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