液晶开机打印信息在我们维修液晶主板的过程中能为我们提供极大的便利，所以维修过程中查看打印信息应该做到常态化，下面我来谈两个利用打印信息维修的案例。
案例1，TCL MS81L机芯数字板
故障现象，开机电源板输出电压正常，主板上各路供电也是正常的，但是主板不输出背光开关信号，屏供电控制信号。
维修步骤：接上串口升级版，配置好SECURECRT终端工具，通电开机，发现打印信息如下：
SPI BOOT
Console Initial OK
Maria10: BD_MST004B_20AVS_10306
MIU: DDR_400Mhz_2x
BIST_0 error.
07 07
[ ]
[ ]
07 07
MIU Initial OK
分析：BIST_0 error. 是典型的DDR检测错误。但这个并不能说明就是DDR坏，因为第一个括号内部没有来自于主芯片的通讯信息，于是在检测完DDR的供电，参考电压后，大致测一遍主芯片于DDR相关的供电，发现正常之后果断更换主芯片，开机故障排除。
案例2 TCL MT01C机芯
故障现象：主板各路供电正常，但是不开机，无背光开关信号，屏供电控制信号。
检修步骤：该现象是典型的CPU工作不正常，于是开机查看打印信息。发现打印信息如下：
Boot-
DRAM Channel A Calibration.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Boot-
DRAM Channel A Calibration.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
相信有过相关经验的朋友都知道，Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
同样是典型的DDR与主芯片通讯不良，由于该主板DDR为BGA封装更换和补焊难度较大，因此重点检测DDR的供电和参考电压正常后，对主芯片进行补焊，发现故障依旧。于是测量主芯片和DDR通讯的排阻，发现一个100欧的排阻变值为1K多，更换该排阻后故障排除。
机型TCL LE32C16 机芯 MST6M48 (MSJ5) 故 障现象指示灯红灯亮不开机
维修过程：将主板上机架通电试机，发现主板上个路基本供电均正常，但指示灯呈待机红色，按按键遥控均无反应。主板无背光开关信号，以及屏供电开启信号输出。根据现象，基本能够判断出该故障系CPU工作不正常所致。连接上串口升级板，打开ISP TOOL升级工具，发现点击连接后软件能够正常识别出FLASH芯片型号，这说明基本上可以确定主芯片MST6M48的基本工作条条件问题应该不大。于是关机配置好SECCURECRT 再开机获取打印信息如下：
BOOTR2AP
INNT
55
[][]
0055 很显然DDR部分工作异常，
于是检测DDR的基本工作条件，发现供电1.8V正常，再测VREF参考电压发9现仅有0.34V，这是显然错误的，该电压应为0.9V左右。电路也很简单如下抓图：
测量R198,R202阻值无异常，A-MVREF对地阻值也无明显异常，怀疑C148漏电，拆除后发现该电压升至0.9V正常。于是以为故障排除，通电试机发现依旧红灯亮不开机。。。郁闷！于是再次获取打印信息，如下：
BOOTR2AP
INNT
55
[3456789ABCD][23456789ABC]
0087
打印至此再无信息。很显然DDR部分通讯已无异常，那么为什么CPU内程序不再跑了呢？按说至此就该运行BOOT了啊，怀疑软件有问题。于是连上升级板对主板进行软件升级，升级完成后，开机故障排除。
案例二。
机芯。TCL MT01C机芯 故障现象，机器通电主板上各路DC-DC输出电压均正常，但是不开机无背光开关信号，屏供电控制信号输出。很显然又是一例CPU工作不正常的。连接升级板，配置好SECCURECRT通电获取打印信息如下：
Boot-
DRAM Channel A Calibration.
Byte 0 : DQS(4 ~ 38), Size 35, Set 19.
Byte 1 : DQS(0 ~ 37), Size 38, Set 16.
DRAM A Size = 128 Mbytes.
Boot
Start Pmain
0x000032a0
NID=0x1d00f1ad
LZHS addr:0x00100040
LZHS size:0x00067220
LZHS checksum:0x000000ff
Boot
Start Lmain
MT5365 Boot Loader v0.9
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF0029000 init ok.
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF002E000 init ok.
Boot reason: A/C power on!!
Load VGA internal EDID.................
DUMMY READ EDID DATA FROM EEPROM
Load HDMI internal EDID.................
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
### EEPROM read loader config failed!!!
Boot reason: A/C power on!!T8032 init A/C on case loader stage...
Load T8032 FW (addr: 0x d54d60, size: 24576)success!! [Page]
LDR_FlashCopy 0xf010 0x30b80 0x80
Switch NAND pinmux
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash(SLC): 128MB
NAND_BDM_Mount: Partid=0, offset=0x0, size=0x100000
[BDM] Partition: 0, Bad Block Count: 0
Do USB upgrade
USB: Vbus turn up time = 452 ms.
No USB device.
USB upgrade stop
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
eeprom write failed, return 1
Boot reason: A/C power on!!
---------test LYQ check eeprom boot-----------
Boot reason: A/C power on!!Org:0x00 Flags:0x10
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
---------test LYQ check eeprom boot-----------
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
Disable VGA wakeup
Standby !
DRAM Channel A Calibration.
Byte 0 : DQS(4 ~ 38), Size 35, Set 19.
Byte 1 : DQS(0 ~ 38), Size 39, Set 17.
DRAM A Size = 128 Mbytes.
Boot
Start Pmain
0x000032a0
NID=0x1d00f1ad
LZHS addr:0x00100040
LZHS size:0x00067220
LZHS checksum:0x000000ff
Boot
Start Lmain
MT5365 Boot Loader v0.9
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF0029000 init ok.
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF002E000 init ok.
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
### EEPROM read loader config failed!!!
T8032 change to loader stage...
LDR_FlashCopy 0xf010 0x30b80 0x80
Switch NAND pinmux
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash(SLC): 128MB
NAND_BDM_Mount: Partid=0, offset=0x0, size=0x100000
[BDM] Partition: 0, Bad Block Count: 0
Do USB upgrade
USB: Vbus turn up time = 433 ms.
No USB device.
USB upgrade stop
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
eeprom write failed, return 1
---------test LYQ check eeprom boot-----------
Org:0x00 Flags:0x10
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
---------test LYQ check eeprom boot-----------
------[_LdrCheckEepromBoot] power mode = standby,ir or button wakeup---------
A_Mute GPIO=326 release
AMP mute GPIO=ca release
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2 [Page]
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
Reset Demod GPIO=320, 0->1
NAND load lzhs header from 0x40000 to dram(0xfe0030), size=2048
Decompression uboot to 0x00f00000...
NAND load image from 0x40000 to dram(0xfe0030), size=0x35cbb
LZHS hardware decode start
LZHS hardware decode done
Starting image...
U-Boot starts...
NAND Flash: Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash: 128MB
128 MiB
Booting sequence is from NAND Flash
In: serial
Out: serial
Err: serial
SIF_Master0: new design
SIF_Master1: old design
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 0
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 1
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 2
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 3
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 4
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 5
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 6
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 7
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 8
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 9
EEPROM_Read() failed
Hit any key to stop autoboot: 0
Partition rootfsA defined at mtdparts:
ID:6, Offset:0x00800000, Size:0x00500000
Loading from nand0, offset 0x600000
Automatic boot of image at addr 0x00008000 ...
## Booting kernel from Legacy Image at 00008000 ...
XIP Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux....................................................................................... done, booting the kernel.
Linux version 2.6.27 (w.y@mtkvm) (gcc version 4.4.2 (GCC for MediaTek 4.4.2-20100324)) #1 PREEMPT Sun Jan 1 06:43:14 WET 2012
CPU: ARMv6-compatible processor [410fb764] revision 4 (ARMv7), cr=00c5387d
Machine: MT5365
Memory policy: ECC disabled, Data cache writeback
CPU0: D VIPT write-back cache
CPU0: I cache: 16384 bytes, associativity 4, 32 byte lines, 128 sets
CPU0: D cache: 16384 bytes, associativity 4, 32 byte lines, 128 sets
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 15494
Kernel command line: root=/dev/mtdblock7 lpj=3506176 console=ttyMT0,115200n1 mtdparts=mt53xx-nand:1M(uboot),1M(uboot_env),1M(sigA),1M(sigB),2M(kernelA),2M(kernelB),5M(rootfsA),5M(rootfsB),28M(basic),70M(rw_area),128k(perm),128k(reserved),2M(channelsA),2M(channelsB),1M(pq),1M(aq),2M(logo)
PID hash table entries: 256 (order: 8, 1024 bytes)
Console: colour dummy device 80x30
console [ttyMT0] enabled
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 61MB = 61MB total
Memory: 59060KB available (2492K code, 147K data, 92K init)
Calibrating delay loop (skipped) preset value.. 1402.47 BogoMIPS (lpj=3506176)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
net_namespace: 288 bytes
NET: Registered protocol family 16
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
NET: Registered protocol family 1
NetWinder Floating Point Emulator V0.97 (double precision)
squashfs: version 3.4 (2008/08/26) Phillip Lougher
msgmni has been set to 115
io scheduler noop registered (default)
Serial: MT5365 driver $Revision: #2 $
ttyMT0 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
ttyMT1 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
ttyMT2 at MMIO 0xf0028800 (irq = 0) is a MT5365 Serial
ttyMT3 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
brd: module loaded
compcache: compcache size not provided. Using default: (25% of Total RAM). [Page]
Use compcache_size_kbytes module param to specify custom size
compcache: Compressed swap size set to: 14780 KB
TLSF: pool: c4009000, init_size=16384, max_size=0, grow_size=16384
PPP generic driver version 2.4.2
PPP Deflate Compression module registered
PPP BSD Compression module registered
NET: Registered protocol family 24
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash: 128MB
NAND device: Manufacturer ID: 0xad, Chip ID: 0xf1 (Hynix NAND 128MiB 3,3V 8-bit)
17 cmdlinepart partitions found on MTD device mt53xx-nand
Creating 17 MTD partitions on "mt53xx-nand":
0x00000000-0x00100000 : "uboot"
0x00100000-0x00200000 : "uboot_env"
0x00200000-0x00300000 : "sigA"
0x00300000-0x00400000 : "sigB"
0x00400000-0x00600000 : "kernelA"
0x00600000-0x00800000 : "kernelB"
0x00800000-0x00d00000 : "rootfsA"
Squshfs - mtdblock6: block 26 is bad!
0x00d00000-0x01200000 : "rootfsB"
0x01200000-0x02e00000 : "basic"
0x02e00000-0x07400000 : "rw_area"
0x07400000-0x07420000 : "perm"
0x07420000-0x07440000 : "reserved"
0x07440000-0x07640000 : "channelsA"
0x07640000-0x07840000 : "channelsB"
0x07840000-0x07940000 : "pq"
0x07940000-0x07a40000 : "aq"
0x07a40000-0x07c40000 : "logo"
TCP cubic registered
NET: Registered protocol family 17
VFS: Mounted root (squashfs filesystem) readonly.
Freeing init memory: 92K
INIT: version 2.86 booting
Mounting local filesystems: mount mount: according to /proc/mounts, /dev/root is already mounted on /
Loading /etc/profile...
Running rc.local...
net.ipv4.tcp_window_scaling = 6
# mount basic
UBI device number 0, total 224 LEBs (28442624 bytes, 27.1 MiB), available 0 LEBs (0 bytes), LEB size 126976 bytes (124.0 KiB)
real 0m 0.09s
user 0m 0.00s
sys 0m 0.05s
UBIFS: recovery needed
UBIFS: recovery completed
real 0m 0.05s
user 0m 0.00s
sys 0m 0.03s
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
DTV>EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 1:32 fail!!
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 1:62 fail!!
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 2:172 fail!!
[_read_project_id_from_eep] eeror Three project id not all same
prj_id_array[0] = 32,prj_id_array[1] = 62,prj_id_array[2] = 172
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 1:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 2:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 3:0 fail!!
[PrjAttributeInit] Read project id fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 1:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
由上述打印信息可以看出DDR ,BOOT,NAND 都基本上检测正常，唯独从
EEPROM_Read() failed
### EEPROM read loader config failed!!!等处可以看出CPU对存储器的读写异常。于是测量存储器总线电压，发现SCL线仅1.2V，SDA线基本正常。对地测试SCL脚对地阻值，发现明显偏度，断开该总线上所连的CPU,以及高频头该阻值依旧很低，怀疑过孔漏电，于是割断过孔铜箔直接飞线连接。开机后SCL电压升至3.3V，开机一切正常。
案例1，TCL MS81L机芯数字板
故障现象，开机电源板输出电压正常，主板上各路供电也是正常的，但是主板不输出背光开关信号，屏供电控制信号。
维修步骤：接上串口升级版，配置好SECURECRT终端工具，通电开机，发现打印信息如下：
SPI BOOT
Console Initial OK
Maria10: BD_MST004B_20AVS_10306
MIU: DDR_400Mhz_2x
BIST_0 error.
07 07
[ ]
[ ]
07 07
MIU Initial OK
分析：BIST_0 error. 是典型的DDR检测错误。但这个并不能说明就是DDR坏，因为第一个括号内部没有来自于主芯片的通讯信息，于是在检测完DDR的供电，参考电压后，大致测一遍主芯片于DDR相关的供电，发现正常之后果断更换主芯片，开机故障排除。
案例2 TCL MT01C机芯
故障现象：主板各路供电正常，但是不开机，无背光开关信号，屏供电控制信号。
检修步骤：该现象是典型的CPU工作不正常，于是开机查看打印信息。发现打印信息如下：
Boot-
DRAM Channel A Calibration.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Boot-
DRAM Channel A Calibration.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
Byte 0 Cal Fail.
Byte 1 Cal Fail.
相信有过相关经验的朋友都知道，Byte 0 Cal Fail.
Byte 1 Cal Fail.
DRAM Input DQS Calibration fail !
同样是典型的DDR与主芯片通讯不良，由于该主板DDR为BGA封装更换和补焊难度较大，因此重点检测DDR的供电和参考电压正常后，对主芯片进行补焊，发现故障依旧。于是测量主芯片和DDR通讯的排阻，发现一个100欧的排阻变值为1K多，更换该排阻后故障排除。
机型TCL LE32C16 机芯 MST6M48 (MSJ5) 故 障现象指示灯红灯亮不开机
维修过程：将主板上机架通电试机，发现主板上个路基本供电均正常，但指示灯呈待机红色，按按键遥控均无反应。主板无背光开关信号，以及屏供电开启信号输出。根据现象，基本能够判断出该故障系CPU工作不正常所致。连接上串口升级板，打开ISP TOOL升级工具，发现点击连接后软件能够正常识别出FLASH芯片型号，这说明基本上可以确定主芯片MST6M48的基本工作条条件问题应该不大。于是关机配置好SECCURECRT 再开机获取打印信息如下：
BOOTR2AP
INNT
55
[][]
0055 很显然DDR部分工作异常，
于是检测DDR的基本工作条件，发现供电1.8V正常，再测VREF参考电压发9现仅有0.34V，这是显然错误的，该电压应为0.9V左右。电路也很简单如下抓图：
测量R198,R202阻值无异常，A-MVREF对地阻值也无明显异常，怀疑C148漏电，拆除后发现该电压升至0.9V正常。于是以为故障排除，通电试机发现依旧红灯亮不开机。。。郁闷！于是再次获取打印信息，如下：
BOOTR2AP
INNT
55
[3456789ABCD][23456789ABC]
0087
打印至此再无信息。很显然DDR部分通讯已无异常，那么为什么CPU内程序不再跑了呢？按说至此就该运行BOOT了啊，怀疑软件有问题。于是连上升级板对主板进行软件升级，升级完成后，开机故障排除。
案例二。
机芯。TCL MT01C机芯 故障现象，机器通电主板上各路DC-DC输出电压均正常，但是不开机无背光开关信号，屏供电控制信号输出。很显然又是一例CPU工作不正常的。连接升级板，配置好SECCURECRT通电获取打印信息如下：
Boot-
DRAM Channel A Calibration.
Byte 0 : DQS(4 ~ 38), Size 35, Set 19.
Byte 1 : DQS(0 ~ 37), Size 38, Set 16.
DRAM A Size = 128 Mbytes.
Boot
Start Pmain
0x000032a0
NID=0x1d00f1ad
LZHS addr:0x00100040
LZHS size:0x00067220
LZHS checksum:0x000000ff
Boot
Start Lmain
MT5365 Boot Loader v0.9
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF0029000 init ok.
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF002E000 init ok.
Boot reason: A/C power on!!
Load VGA internal EDID.................
DUMMY READ EDID DATA FROM EEPROM
Load HDMI internal EDID.................
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
### EEPROM read loader config failed!!!
Boot reason: A/C power on!!T8032 init A/C on case loader stage...
Load T8032 FW (addr: 0x d54d60, size: 24576)success!! [Page]
LDR_FlashCopy 0xf010 0x30b80 0x80
Switch NAND pinmux
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash(SLC): 128MB
NAND_BDM_Mount: Partid=0, offset=0x0, size=0x100000
[BDM] Partition: 0, Bad Block Count: 0
Do USB upgrade
USB: Vbus turn up time = 452 ms.
No USB device.
USB upgrade stop
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
eeprom write failed, return 1
Boot reason: A/C power on!!
---------test LYQ check eeprom boot-----------
Boot reason: A/C power on!!Org:0x00 Flags:0x10
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
---------test LYQ check eeprom boot-----------
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
Disable VGA wakeup
Standby !
DRAM Channel A Calibration.
Byte 0 : DQS(4 ~ 38), Size 35, Set 19.
Byte 1 : DQS(0 ~ 38), Size 39, Set 17.
DRAM A Size = 128 Mbytes.
Boot
Start Pmain
0x000032a0
NID=0x1d00f1ad
LZHS addr:0x00100040
LZHS size:0x00067220
LZHS checksum:0x000000ff
Boot
Start Lmain
MT5365 Boot Loader v0.9
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF0029000 init ok.
MUSB none SoftReset 0x29424 = 0x01030000.
MUSB pBase = 0xF002E000 init ok.
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
### EEPROM read loader config failed!!!
T8032 change to loader stage...
LDR_FlashCopy 0xf010 0x30b80 0x80
Switch NAND pinmux
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash(SLC): 128MB
NAND_BDM_Mount: Partid=0, offset=0x0, size=0x100000
[BDM] Partition: 0, Bad Block Count: 0
Do USB upgrade
USB: Vbus turn up time = 433 ms.
No USB device.
USB upgrade stop
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
eeprom write failed, return 1
---------test LYQ check eeprom boot-----------
Org:0x00 Flags:0x10
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
---------test LYQ check eeprom boot-----------
------[_LdrCheckEepromBoot] power mode = standby,ir or button wakeup---------
A_Mute GPIO=326 release
AMP mute GPIO=ca release
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2 [Page]
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
Reset Demod GPIO=320, 0->1
NAND load lzhs header from 0x40000 to dram(0xfe0030), size=2048
Decompression uboot to 0x00f00000...
NAND load image from 0x40000 to dram(0xfe0030), size=0x35cbb
LZHS hardware decode start
LZHS hardware decode done
Starting image...
U-Boot starts...
NAND Flash: Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash: 128MB
128 MiB
Booting sequence is from NAND Flash
In: serial
Out: serial
Err: serial
SIF_Master0: new design
SIF_Master1: old design
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 0
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 1
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 2
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 3
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 4
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 5
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 6
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 7
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 8
eeprom para:140(6ffc90) u4MemLen:0x00000009
EEPROM_Read() 9
EEPROM_Read() failed
Hit any key to stop autoboot: 0
Partition rootfsA defined at mtdparts:
ID:6, Offset:0x00800000, Size:0x00500000
Loading from nand0, offset 0x600000
Automatic boot of image at addr 0x00008000 ...
## Booting kernel from Legacy Image at 00008000 ...
XIP Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux....................................................................................... done, booting the kernel.
Linux version 2.6.27 (w.y@mtkvm) (gcc version 4.4.2 (GCC for MediaTek 4.4.2-20100324)) #1 PREEMPT Sun Jan 1 06:43:14 WET 2012
CPU: ARMv6-compatible processor [410fb764] revision 4 (ARMv7), cr=00c5387d
Machine: MT5365
Memory policy: ECC disabled, Data cache writeback
CPU0: D VIPT write-back cache
CPU0: I cache: 16384 bytes, associativity 4, 32 byte lines, 128 sets
CPU0: D cache: 16384 bytes, associativity 4, 32 byte lines, 128 sets
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 15494
Kernel command line: root=/dev/mtdblock7 lpj=3506176 console=ttyMT0,115200n1 mtdparts=mt53xx-nand:1M(uboot),1M(uboot_env),1M(sigA),1M(sigB),2M(kernelA),2M(kernelB),5M(rootfsA),5M(rootfsB),28M(basic),70M(rw_area),128k(perm),128k(reserved),2M(channelsA),2M(channelsB),1M(pq),1M(aq),2M(logo)
PID hash table entries: 256 (order: 8, 1024 bytes)
Console: colour dummy device 80x30
console [ttyMT0] enabled
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 61MB = 61MB total
Memory: 59060KB available (2492K code, 147K data, 92K init)
Calibrating delay loop (skipped) preset value.. 1402.47 BogoMIPS (lpj=3506176)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
net_namespace: 288 bytes
NET: Registered protocol family 16
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
NET: Registered protocol family 1
NetWinder Floating Point Emulator V0.97 (double precision)
squashfs: version 3.4 (2008/08/26) Phillip Lougher
msgmni has been set to 115
io scheduler noop registered (default)
Serial: MT5365 driver $Revision: #2 $
ttyMT0 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
ttyMT1 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
ttyMT2 at MMIO 0xf0028800 (irq = 0) is a MT5365 Serial
ttyMT3 at MMIO 0xf000c000 (irq = 17) is a MT5365 Serial
brd: module loaded
compcache: compcache size not provided. Using default: (25% of Total RAM). [Page]
Use compcache_size_kbytes module param to specify custom size
compcache: Compressed swap size set to: 14780 KB
TLSF: pool: c4009000, init_size=16384, max_size=0, grow_size=16384
PPP generic driver version 2.4.2
PPP Deflate Compression module registered
PPP BSD Compression module registered
NET: Registered protocol family 24
Detect NAND flash ID: 0x1D00F1AD
Detect HY27U1G8F2BTR NAND flash: 128MB
NAND device: Manufacturer ID: 0xad, Chip ID: 0xf1 (Hynix NAND 128MiB 3,3V 8-bit)
17 cmdlinepart partitions found on MTD device mt53xx-nand
Creating 17 MTD partitions on "mt53xx-nand":
0x00000000-0x00100000 : "uboot"
0x00100000-0x00200000 : "uboot_env"
0x00200000-0x00300000 : "sigA"
0x00300000-0x00400000 : "sigB"
0x00400000-0x00600000 : "kernelA"
0x00600000-0x00800000 : "kernelB"
0x00800000-0x00d00000 : "rootfsA"
Squshfs - mtdblock6: block 26 is bad!
0x00d00000-0x01200000 : "rootfsB"
0x01200000-0x02e00000 : "basic"
0x02e00000-0x07400000 : "rw_area"
0x07400000-0x07420000 : "perm"
0x07420000-0x07440000 : "reserved"
0x07440000-0x07640000 : "channelsA"
0x07640000-0x07840000 : "channelsB"
0x07840000-0x07940000 : "pq"
0x07940000-0x07a40000 : "aq"
0x07a40000-0x07c40000 : "logo"
TCP cubic registered
NET: Registered protocol family 17
VFS: Mounted root (squashfs filesystem) readonly.
Freeing init memory: 92K
INIT: version 2.86 booting
Mounting local filesystems: mount mount: according to /proc/mounts, /dev/root is already mounted on /
Loading /etc/profile...
Running rc.local...
net.ipv4.tcp_window_scaling = 6
# mount basic
UBI device number 0, total 224 LEBs (28442624 bytes, 27.1 MiB), available 0 LEBs (0 bytes), LEB size 126976 bytes (124.0 KiB)
real 0m 0.09s
user 0m 0.00s
sys 0m 0.05s
UBIFS: recovery needed
UBIFS: recovery completed
real 0m 0.05s
user 0m 0.00s
sys 0m 0.03s
SIF_Master0: new design
SIF_Master1: old design
EEPROM_Read() 0
DTV>EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 1:32 fail!!
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 1:62 fail!!
EEPROM_Read() 0
EEPROM_Read() 1
EEPROM_Read() 2
EEPROM_Read() 3
EEPROM_Read() 4
EEPROM_Read() 5
EEPROM_Read() 6
EEPROM_Read() 7
EEPROM_Read() 8
EEPROM_Read() 9
EEPROM_Read() failed
[_read_project_id_from_eep] 2:172 fail!!
[_read_project_id_from_eep] eeror Three project id not all same
prj_id_array[0] = 32,prj_id_array[1] = 62,prj_id_array[2] = 172
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 1:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 2:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 3:0 fail!!
[PrjAttributeInit] Read project id fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
EEPROM_Write() 7
EEPROM_Write() 8
EEPROM_Write() 9
EEPROM_Write() failed
[_write_project_id_to_eep] 1:0 fail!!
EEPROM_Write() 0
EEPROM_Write() 1
EEPROM_Write() 2
EEPROM_Write() 3
EEPROM_Write() 4
EEPROM_Write() 5
EEPROM_Write() 6
由上述打印信息可以看出DDR ,BOOT,NAND 都基本上检测正常，唯独从
EEPROM_Read() failed
### EEPROM read loader config failed!!!等处可以看出CPU对存储器的读写异常。于是测量存储器总线电压，发现SCL线仅1.2V，SDA线基本正常。对地测试SCL脚对地阻值，发现明显偏度，断开该总线上所连的CPU,以及高频头该阻值依旧很低，怀疑过孔漏电，于是割断过孔铜箔直接飞线连接。开机后SCL电压升至3.3V，开机一切正常。
版权声明：本文为转载文章，版权归原作者所有，欢迎分享本文，转载请保留出处！