Notes:
•Make sure that you use the correct screw. If you have a torque screwdriver, tighten all screws firmly to the torque shown in the table for each step in Chapter 8 “Removing and replacing a FRU” on page 49. Never use a screw that you removed. Use a new one. Make sure that all of the screws are tightened firmly.
•Ensure torque screwdrivers are calibrated correctly following country specifications.
Retaining serial numbers
This topic provides instructions on the following:
•“Restoring the serial number of the system unit” on page 46
•“Retaining the UUID” on page 47
•“Reading or writing the ECA information” on page 47
Restoring the serial number of the system unit
When the computer was manufactured, the EEPROM on the system board was loaded with the serial numbers of the system and all major components. These numbers need to remain the same throughout the life of the computer.
If you replace the system board, you must restore the serial number of the system board to its original value.
Before replacing the system board, save the original serial number by doing the following:
1.Install the LENOVO ThinkPad Hardware Maintenance Diskette Version 1.76 or later, and restart the computer.
2.From the main menu, select 1. Set System Identification.
3.Select 2. Read S/N data from EEPROM.
The serial number of each device in your computer is displayed. The serial number of the system board is listed is listed as 20: Serial number.
Write down that number.
Note: The serial number of the system board is also written on the label attached to the bottom of the computer.
After you have replaced the system board, restore the serial number by doing the following:
1.Install the LENOVO ThinkPad Hardware Maintenance Diskette Version 1.76 or later and restart the computer.
2.From the main menu, select 1. Set System Identification.
3.Select 1. Add S/N data from EEPROM. Follow the instructions on the screen.
If the MTM and Product ID numbers differ from each other on the rear label, use what is shown for the Product ID field. See example below: