Copyright Lenovo; Chapter 6. Fru Replacement Notices; Screw Notices - Lenovo B575e Hardware Maintenance Manual

Chapter 6. FRU replacement notices

This chapter presents notices related to removing and replacing parts. Read this chapter carefully before
replacing any FRU.

Screw notices

Loose screws can cause a reliability problem. In the Lenovo notebook 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.
Do the following when you service the computer:
• Keep the screw kit in your tool bag.
• It is recommended to use new screws.
• It recommended to use each screw only once.
• Use a torque screwdriver if you have one.
Tighten screws as follows:
• Plastic to plastic
Turn an additional 90 degrees after the screw head touches the surface of the plastic part.
• Logic card to plastic
Turn an additional 180 degrees after the screw head touches the surface of the logic card.
• Torque driver
If you have a torque screwdriver, refer to the Torque column in the screw information table for each step.
• Ensure that you use the correct screw. It is recommended to use new screws for replacements. If you
have a torque screwdriver, tighten all screws firmly to the torque specified in the screw information
table for each step.
• Ensure that torque screw drivers are calibrated correctly following country specifications.
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