Lenovo ThinkPad T420si Hardware Maintenance Manual page 91

Note: In models with the fingerprint reader, the sensor is attached to the palm rest FRU. If the fingerprint
reader is defective, you can replace the palm rest by following the procedures in this section. The
replacement procedures are the same for a palm rest with or without a fingerprint reader.
Removal steps of palm rest or palm rest with fingerprint reader
Step Screw (quantity)
1
M2 × 5 mm, flat-head, nylon-coated (13)
2
M2.5 × 5 mm, flat-head, nylon-coated (2)
3
M2 × 3 mm, flat-head, nylon-coated (1)
Step Screw (quantity)
4
M2 × 5 mm, flat-head, nylon-coated (3)
Color Torque
Black 0.181 Nm
(1.85 kgfcm)
Black 0.181 Nm
(1.85 kgfcm)
Silver 0.181 Nm
(1.85 kgfcm)
Torque
Color
Black 0.181 Nm
(1.85 kgfcm)
.
Chapter 8 Removing and replacing a FRU
85