FRU replacement noticesThis chapter presents notices related to removing and replacing parts. Read thischapter carefully before replacing any FRU.Screw noticesLoose screws can cause a reliability problem. In the ThinkPad Notebook, thisproblem is addressed with special nylon-coated screws that have the followingcharacteristics: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 159) in yourtool bag.v Always use new screws.v Use a torque screwdriver if you have one.Tighten screws as follows:v Plastic to plasticTurn an additional 90 degrees after the screw head touches the surface of theplastic part:90 degrees more(Cross-section)v Logic card to plasticTurn an additional 180 degrees after the screw head touches the surface of thelogic card:180 degrees more(Cross-section)v Torque driverIf 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 screwthat you removed. Use a new one. Make sure that all of the screws aretightened firmly.v Ensure torque screw drivers are calibrated correctly following countryspecifications.© Copyright Lenovo 2009 77
