ThinkPad T420 and T420i Hardware Maintenance Manual
Fourth Edition November Copyright Lenovo
Contents
Locations 125
About this manual
Iii
Iv ThinkPad T420 and T420i Hardware Maintenance Manual
Safety information
General safety
Electrical safety
Safety inspection guide
Grounding requirements
Safety notices multilingual translations
ThinkPad T420 and T420i Hardware Maintenance Manual
Perigo
Perigo
Perigo
Vorsicht
Vorsicht
ThinkPad T420 and T420i Hardware Maintenance Manual
Safety information
ThinkPad T420 and T420i Hardware Maintenance Manual
Safety information
ThinkPad T420 and T420i Hardware Maintenance Manual
Laser compliance statement multilingual translations
ThinkPad T420 and T420i Hardware Maintenance Manual
Safety information
ThinkPad T420 and T420i Hardware Maintenance Manual
Safety information
ThinkPad T420 and T420i Hardware Maintenance Manual
Strategy for replacing FRUs
Important service information
Before replacing parts
Strategy for replacing a hard disk drive
How to use error message
Important notice for replacing a system board
FRU identification for CTO, CMV, and GAV products
Dynamic Configure To Order CTO
Using PEW
Custom Model Variant CMV
ThinkPad T420 and T420i Hardware Maintenance Manual
General checkout
Following are not covered under warranty
What to do first
Diagnostics using PC-Doctor for DOS
Checkout guide
Diagnostics Interactive Tests
Options on the test menu are as follows
Hardware Info
Lenovo ThinkVantage Toolbox
Windows
Utility
ThinkPad T420 and T420i Hardware Maintenance Manual
FRU tests
Checking operational charging
Power system checkout
Checking the ac power adapter
Pin Voltage V dc
Checking the backup battery
Checking the battery pack
Terminal Voltage V dc
Wire Voltage V dc
Related service information
Restoring the factory contents by using Recovery Disc Set
Power-on password
Passwords
Hard-disk password
How to remove the hard-disk password
Supervisor password
How to remove the power-on password
Select Power-On Password
Select Master HDP
Sleep standby mode
Power management
Screen blank mode
Hibernation mode
ThinkPad T420 and T420i Hardware Maintenance Manual
Symptom-to-FRU index
Numeric error codes
By connecting the ac power adapter
0199 Run the ThinkPad Setup program, and then save
0251 Charge the backup battery for more than 8 hours
0271 Run the ThinkPad Setup program to reset the time
Replace the battery
Error messages
Symptom or error FRU or action, in sequence
Fan
No-beep symptoms
Beep symptoms
LCD-related symptoms
See important note for LCD-related symptoms
Reseat the LCD connectors
LCD assembly
Intermittent problems
Undetermined problems
Status indicators
Indicator Meaning
Green
Indicator Meaning
Battery status indicator blinks three times
Blinking green
Battery status indicator is off
Key combination Description
Fn key combinations
For Windows
For Windows Vista and Windows XP
Fn key combinations
ThinkPad T420 and T420i Hardware Maintenance Manual
External CRU statement to customers
FRU replacement notices
Screw notices
Plastic to plastic
Torque driver
Retaining serial numbers
Restoring the serial number of the system unit
Select 2. Read S/N data from Eeprom
MTM on rear label
Retaining the Uuid
Reading or writing the ECA information
Product ID on rear label
ThinkPad T420 and T420i Hardware Maintenance Manual
Removing and replacing a FRU
Before servicing ThinkPad T420 and T420i
Battery pack
Important notice for replacing a battery pack
ExpressCard blank bezel
Removal steps of ExpressCard blank bezel
Serial Ultrabay Enhanced device or travel bezel
Hard disk drive HDD and solid state drive SSD
Removal steps of hard disk drive and solid state drive
Removing and replacing a FRU
ThinkPad T420 and T420i Hardware Maintenance Manual
Dimm slot cover
Removal steps of Dimm slot cover
Dimm in the slot on the underside of the computer
Removal steps of PCI Express Mini Card for wireless WAN
PCI Express Mini Card for wireless WAN
Step Screw quantity Color Torque
ThinkPad T420 and T420i Hardware Maintenance Manual
Keyboard
Removal steps of keyboard
Installation steps of keyboard
Removing and replacing a FRU
ThinkPad T420 and T420i Hardware Maintenance Manual
Dimm in the slot under the keyboard
Removal steps of Dimm in the slot under the keyboard
ThinkPad T420 and T420i Hardware Maintenance Manual
Backup battery
ThinkPad T420 and T420i Hardware Maintenance Manual
PCI Express Mini Card for wireless LAN
Removal steps of PCI Express Mini Card for wireless LAN
When installing
Step Screw quantity Color Torque
Step Screw quantity Color Torque
Removing and replacing a FRU
M2 × 3 mm, wafer-head, nylon-coated Black 181 Nm Kgfcm
Removing and replacing a FRU
SmartCard
Removal steps of SmartCard
Removal steps of SmartCard dummy spacer
Modem daughter card MDC
Removal steps of modem daughter card MDC
Speaker assembly
Removal steps of speaker assembly
ThinkPad T420 and T420i Hardware Maintenance Manual
LCD unit
Removal steps of LCD unit
M2 × 3 mm, wafer-head, nylon-coated Black 181 Nm Kgfcm
When installing
ThinkPad T420 and T420i Hardware Maintenance Manual
Fan assembly
Step Screw quantity Color Torque
For Integreted Graphics models When installing
For Discrete Graphics models For Integrated Graphics models
ThinkPad T420 and T420i Hardware Maintenance Manual
1180 CPU
Removal steps of CPU
Base cover assembly and DC-in connector cable
M2 × 5 mm, wafer-head, nylon-coated Black 181 Nm Kgfcm
M2 × 3 mm, wafer-head, nylon-coated Black 181 Nm Kgfcm
Removing and replacing a FRU
Magnesium structure frame
Removal steps of magnesium structure frame
Removing and replacing a FRU
Removal steps of system board and ExpressCard slot assembly
System board and ExpressCard slot assembly
Important notices for handling the system board
Removing and replacing a FRU
MSATA solid state drive
Removal steps of mSATA solid state drive
LCD bezel assembly
Removal steps of LCD bezel assembly
LED board
Removal steps of LED board
ThinkPad T420 and T420i Hardware Maintenance Manual
Integrated camera
Removal steps of integrated camera
ThinkPad T420 and T420i Hardware Maintenance Manual
LCD panel and LCD cable
Removal steps of LCD panel and LCD cable
ThinkPad T420 and T420i Hardware Maintenance Manual
Camera cable
Removal steps of camera cable
ThinkPad T420 and T420i Hardware Maintenance Manual
Step Screw quantity Color Torque
Hinges and LCD rear cover assembly
Removal steps of hinges and LCD rear cover assembly
Removing and replacing a FRU
ThinkPad T420 and T420i Hardware Maintenance Manual
Front view
Locations
125
ThinkPad T420 and T420i Hardware Maintenance Manual
Rear view
Bottom view
129
Parts list
External CRU statement to customers
Overall
CRU ID
FRU Overall FRU no
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
CRU ID
LCD FRUs
CRU
No. FRU FRU no
Camera module 60Y9994
FRU
FRU
Language FRU no
CRU
Miscellaneous parts
FRU
Information about ac power adapters
Power cords
Country or region FRU no
Windows Vista Business 32 bit SP2 DVDs
Recovery discs
Windows XP Professional DVDs
Language
Windows 7 Professional 64 bit DVDs
Windows Vista Home Basic 32 bit SP2 DVDs
Windows 7 Professional 32 bit DVDs
US English 04T1312
Parts list-Windows 7 Professional 64 bit recovery DVDs
Windows 7 Home Basic 32 bit DVDs
Windows 7 Home Premium 32 bit DVDs
Windows 7 Home Premium 64 bit DVDs
US English 04T1321
Windows 7 Ultimate 32 bit DVDs
Windows 7 Ultimate 64 bit DVDs
US English 04T1349
Common service tools
Tool
Appendix A. Notices
167
Electronic emissions notices
Trademarks
ThinkPad T420 and T420i Hardware Maintenance Manual
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