Lenovo ThinkPad T400 Maintenance Manual page 70

Reading or writing the ECA information
Information on Engineering Change Announcements (ECA) are stored in the
EEPROM of the system board. The electronic storage of this information simplifies
the procedure to check if the ECA has been previously applied to a machine. The
machine does not need to be disassembled to check for the ECA application.
To check what ECAs have been previously applied to the machine, use the ECA
Information Read/Write function on the ThinkPad Hardware Maintenance Diskette
Version 1.73 or later.
1. Insert the ThinkPad Hardware Maintenance Diskette Version 1.73 or later, and
2. From the main menu, select 6. Set ECA Information.
3. To read ECA information, select 2. Read ECA/rework number from EEPROM
4. To read box build date, select 5. Read box build date from EEPROM, and
After an ECA has been applied to the machine, the EEPROM must be updated to
reflect the ECA's application. Use the ThinkPad Hardware Maintenance Diskette
Version 1.73 or later to update the EEPROM.
Note: Only the ECA number is stored in the EEPROM. The machine type of the
ECA is assumed be the same as the machine type of the machine that had the ECA
applied to it.
1. Insert the ThinkPad Hardware Maintenance Diskette Version 1.73 or later, and
2. From the main menu, select 6. Set ECA Information.
3. To write ECA information, select 1. Write ECA/rework number from EEPROM,
4. To write box build date, select 4. Write box build date from EEPROM, and
If the system board is being replaced, try to read the ECA information from the old
system board and transfer the information to the new system. If the system board
is inoperable, this will not be possible.
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ThinkPad T400 and R400 Hardware Maintenance Manual
restart the computer.
and follow the instruction.
follow the instruction on the screen.
restart the computer.
and follow the instruction.
follow the instruction on the screen.