Reading Or Writing The Eca Information - Lenovo ThinkPad T550 Hardware Maintenance Manual

Reading or writing the ECA information

Information on Engineering Change Announcements (ECA) is 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 USB Maintenance Key.
1. Insert the Maintenance Key and restart the computer.
2. From the main menu, select 6. Set ECA Information.
3. To read the ECA information, select 2. Read ECA/rework number from EEPROM and follow the
instructions on the screen.
4. To read the box build date, select 5. Read box build date from EEPROM, and follow the instruction on
the screen.
After an ECA has been applied to the machine, the EEPROM must be updated to reflect the ECA's
application. Use the Maintenance Key to update the EEPROM.
Note: Only the ECA number is stored in the EEPROM. The machine type of the ECA is assumed to be the
same as the machine type of the machine that had the ECA applied to it.
1. Insert the Maintenance Key and restart the computer.
2. From the main menu, select 6. Set ECA Information.
3. To write the ECA information, select 1. Write ECA/rework number from EEPROM, and follow the
instructions on the screen.
4. To write the box build date, select 4. Write box build date from EEPROM, and follow the instruction on
the screen.
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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Hardware Maintenance Manual