接修一張TCL售後的板子，手上剛好有同型號的板子就先給他解決用戶問題了，今天有時間拿出來修下，有幾個我之前沒有遇到的問題所以寫了篇筆記。
主板板號：40-T96804-MAB2HG
電視機芯：T968A1
芯片方案：amlogic T968-H
故障現象：指示燈亮不開機
客戶拿來時候已經在別的地方修過，他重新升過系統，但是故障沒有變化。別人已經判了死刑了，對這種二手故障機我修的時候習慣性先看他動了哪裡，主芯片應該是補焊過。別的沒發現動過哪裡。
通電之前測了幾個主要的供電點沒有短路，連接愛修網的RT809H通電看有沒有打印信息，有打印心中暗喜：
從打印信息看應該是主芯片沒有工作，但是這個板子修過很多塊都是U800壞引起的，也是本著先易後難的原則，換了一個U800，寫入備份，再裝回看打印信息，結果和上面的一樣。測量復位發現只有2.5v，明顯不對，找到後仔細觀察復位電路，被動過，R814電阻被去掉了。於是找圖紙看看多大的，圖紙標註為100Ω，R813、R816、R853、R803，幾個阻值都和圖紙的不一樣，因為我的基礎比較差，所以都按圖紙上的換了，換後復位3.3v正常了，但是仍然沒有打印信息。
接下來開始檢查各路供電及其對地壓降、復位和時鐘，未發現明顯異常的地方，於是換主芯片，這就讓我開始了苦逼的換芯之路，連換3片都沒有打印，第4片打印信息出來了:
老師指導說數據總線正常，地址總線的問題，這樣的指導讓我省了很多的測量工作，這個芯片架構的DDR1在芯片的頂部兩片DDR。經測量發現R669、R671壓降明顯不對，拆卸DDR測量還是這兩個地方不對，仍然是CPU 的問題，最後換了一片，打印信息正常了，圖像也出來了。
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
至此本機修復完畢，芯片問題很糟心。
報名聯繫方式
國內
電話：020-28667686（潘老師）
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