Dell Precision 390 - Manual (Page 105)

3. Remove the front panel. See Removing the Front Panel .
4. Remove any components that restrict access to the system board.
5. Disconnect all cables from the system board.
6. Before you remove the existing system board assembly, visually compare the replacement system board to the existing system board to make sure that
you have the correct part.
7. Remove the system board screws.
8. Pull up on the two tabs, slide the system board assembly toward the front of the computer, and then lift the assembly up and away.
9. Place the system board assembly that you just removed next to the replacement system board.
1 system board 2 screws
Replacing the System Board
1. Transfer components from the existing system board to the replacement system board:
a. Remove the memory modules and install them on the replacement board. See Memory for more information.
b. Remove the heat-sink assembly and processor from the existing system board and transfer them to the replacement system board. See
Processor for more information.
2. Set the jumpers on the replacement system board so that they are identical to the ones on the existing board (see System Board Components ).
1 system board 2 back of computer
CAUTION: The processor package and heat-sink assembly can get hot. To avoid burns, ensure that the package and assembly have had sufficient
time to cool before you touch them.
NOTE: Some components and connectors on the replacement system board may be in different locations than the corresponding connectors on the
existing system board.