User Guide

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 ThinkPad Notebook, this

problem is addressed with special nylon-coated screws that have the following

characteristics:

v They maintain tight connections.

v They do not easily come loose, even with shock or vibration.

v They are harder to tighten.

v Each one should be used only once.

Do the following when you service this machine:

v Keep the screw kit (for the P/N, see “Miscellaneous parts” on page 239) in your

tool bag.

v Always use new screws.

v Use a torque screwdriver if you have one.

Tighten screws as follows:

v Plastic to plastic

Turn an additional 90 degrees after the screw head touches the surface of the

plastic part:

90 degrees more

(Cross-section)

v Logic card to plastic

Turn an additional 180 degrees after the screw head touches the surface of the

logic card:

180 degrees more

(Cross-section)

v Torque driver

If you have a torque driver, refer to the “Torque” column for each step.

v Make sure that you use the correct screw. 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 of the screws are

tightened firmly.

v Ensure torque screw drivers are calibrated correctly following country

specifications.