Lenovo ThinkPad T420 4177 Hardware Maintenance Manual page 104

Table 26. System board, fan assembly, 34-mm ExpressCard reader, and base cover (continued)
5
In step , remove the system board with fan assembly together from the base cover assembly.
Turn the system board over, and then disconnect the fan assembly from the system board.
Step Screw (quantity)
7
M2 × 5 mm, big-head, nylon-coated (4)
96
Hardware Maintenance Manual
Color Torque
Black 0.181 Nm
(1.85 kgfcm)