Lenovo ThinkStation 4215 Hardware Maintenance Manual page 110

CAUTION:
The heat sink and microprocessor might be very hot. Turn off the computer and
wait three to five minutes to let the computer cool before removing the
computer cover.
Note: When replacing the system board, you must order a new retention module
To replace the system board, do the following:
10. Remove the eight screws that secure the system board to the chassis,
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Hardware Maintenance Manual
for the new system board. Make sure you have a retention module for the
new system board before continuing this procedure.
1. Remove all media from the drives and turn off all attached devices and the
computer. Then, disconnect all power cords from electrical outlets and
disconnect all cables that are connected to the computer.
2. Remove the computer cover. See "Removing the computer cover" on page 87.
3. Lay the computer on its side for easier access to the system board.
4. Remove all memory modules and PCI cards that are currently installed. See
"Installing or replacing a memory module" on page 92 and "Installing or
replacing a PCI card" on page 90.
5. Remove the secondary hard disk drive. See "Replacing the secondary hard
disk drive" on page 109.
6. Remove the heat sink and fan assembly from the failing system board. See
"Replacing the heat sink and fan assembly" on page 99.
7. Remove the microprocessor from the failing system board. See "Replacing the
microprocessor" on page 101.
8. Remove the battery from the failing system board. See "Replacing the battery"
on page 98.
9. Note the location of all cable connections on the system board and disconnect
all cables. See "Locating parts on the system board" on page 86.
following the sequence shown in the illustration: