Lenovo B50-45 Hardware Maintenance Manual - Lenovo B50-xx, B50-30 Touch Notebo - Page 35

Lenovo B50-30/B50-30 Touch/B50-45/B50-70 FRU replacement notices This section presents notices related to removing and replacing parts. Read this section carefully before replacing any FRU. Screw notices Loose screws can cause a reliability problem. In the Lenovo computer, this problem is addressed with special nylon‐coated screws that have the following characteristics: • They maintain tight connections. • They do not easily come loose, even with shock or vibration. • They are harder to tighten. • Each one should be used only once. Do the following when you service this machine: • Keep the screw kit in your tool bag. • Remove screws carefully for reuse. • Use a torque screwdriver if you have one. Tighten screws as follows: • Plastic to plastic Turn an additional 90° after the screw head touches the surface of the plastic part: more than 90° (Cross-section) • Logic card to plastic Turn an additional 180° after the screw head touches the surface of the logic card: more than 180° (Cross-section) • Torque driver If you have a torque screwdriver, refer to the "Torque" column for each step. • Make sure that you use the correct screws. If you have a torque screwdriver, tighten all screws firmly to the torque shown in the table. Never use a screw that you removed. Use a new one. Make sure that all screws are tightened firmly. • Ensure torque screwdrivers are calibrated correctly following country specifications. 31