Lenovo ThinkPad L420 Hardware Maintenance Manual page 102

Removal steps of USB connector board and USB cable assembly
When installing: Make sure that the connectors are attached firmly.
Step Screw (quantity)
2
M2 × 3 mm, flat-head, nylon-coated (1)
Cable routing: Route the USB cable assembly as shown in the following figures.
For ThinkPad L520 models:
For ThinkPad L420 and L421 models:
96
Hardware Maintenance Manual
1
Torque
Color
Black 0.181 Nm
(1.85 kgfcm)