Lenovo T420 User Manual
Page 3
Contents
About this manual. . . . . . . . . . .
Chapter 1. Safety information . . . . . . 1
General safety . . . . . . . . . . . . . . . .
Electrical safety . . . . . . . . . . . . . . .
Safety inspection guide . . . . . . . . . . . .
Handling devices that are sensitive to electrostatic
discharge. . . . . . . . . . . . . . . . . .
Grounding requirements . . . . . . . . . . . .
Safety notices (multilingual translations) . . . . . .
Laser compliance statement (multilingual
translations) . . . . . . . . . . . . . . . .
Chapter 2. Important service
information . . . . . . . . . . . . . .
Strategy for replacing FRUs . . . . . . . . .
Strategy for replacing a hard disk drive . . .
Important notice for replacing a system
board . . . . . . . . . . . . . . . .
How to use error message . . . . . . . .
Strategy for replacing FRUs for CTO, CMV, and
GAV . . . . . . . . . . . . . . . . . . .
Product definition . . . . . . . . . . . .
FRU identification for CTO, CMV, and GAV
products . . . . . . . . . . . . . . .
Chapter 3. General checkout . . . . .
What to do first . . . . . . . . . . . . . .
Checkout guide . . . . . . . . . . . . . .
Diagnostics using PC-Doctor for DOS. . . .
Lenovo ThinkVantage Toolbox . . . . . . .
FRU tests . . . . . . . . . . . . . . .
Power system checkout . . . . . . . . . . .
Checking the ac power adapter . . . . . .
Checking the battery pack . . . . . . . .
Checking the backup battery . . . . . . .
Chapter 4. Related service
information . . . . . . . . . . . . . .
Restoring the factory contents by using Recovery
Disc Set . . . . . . . . . . . . . . . . .
Passwords . . . . . . . . . . . . . . . .
Power-on password . . . . . . . . . . .
Hard-disk password. . . . . . . . . . .
Supervisor password . . . . . . . . . .
How to remove the power-on password . . .
How to remove the hard-disk password . . .
Screen blank mode . . . . . . . . . . .
Sleep (standby) mode . . . . . . . . . .
Symptom-to-FRU index . . . . . . . . . . .
Beep symptoms . . . . . . . . . . . .
No-beep symptoms . . . . . . . . . . .
LCD-related symptoms . . . . . . . . .
Intermittent problems . . . . . . . . . .
Undetermined problems . . . . . . . . .
Chapter 5. Status indicators . . . . .
Chapter 6. Fn key combinations . . .
Chapter 7. FRU replacement
notices . . . . . . . . . . . . . . . .
Screw notices . . . . . . . . . . . . . . .
Retaining serial numbers. . . . . . . . . . .
Restoring the serial number of the system
unit . . . . . . . . . . . . . . . . .
Retaining the UUID . . . . . . . . . . .
Reading or writing the ECA information . . .
Chapter 8. Removing and replacing a
FRU . . . . . . . . . . . . . . . . . .
Before servicing ThinkPad T420 and T420i
1010 Battery pack . . . . . . . . . . . . .
1020 ExpressCard blank bezel . . . . . . . .
1030 Serial Ultrabay Enhanced device or travel
bezel . . . . . . . . . . . . . . . . . .
1040 Hard disk drive (HDD) and solid state drive
(SSD) . . . . . . . . . . . . . . . . . .
1050 DIMM slot cover . . . . . . . . . . . .
1060 DIMM (in the slot on the underside of the
computer)
. . . . . . . . . . . . . . . .
1070 PCI Express Mini Card for wireless WAN . .
1080 Keyboard . . . . . . . . . . . . . .
1090 DIMM (in the slot under the keyboard) . . .
1100 Backup battery . . . . . . . . . . . .
1110 PCI Express Mini Card for wireless LAN . .
1120 Keyboard bezel assembly, FPC cable, and
Bluethooth daughter card . . . . . . . . . .
1130 SmartCard . . . . . . . . . . . . . .
1140 Modem daughter card (MDC). . . . . . .
1150 Speaker assembly . . . . . . . . . . .
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