Chapter 7. 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:
• 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 (for the P/N, see “Miscellaneous parts” on page 90) in your tool bag.
• Always use new screws.
• 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 driver, refer to the “Torque” column for each step.
• 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.
• Ensure torque screw drivers are calibrated correctly following country specifications.
© Copyright Lenovo 2011
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Summary of Contents for 440128U
Page 1: ...Hardware Maintenance Manual ThinkPad Edge E420s ...
Page 6: ...iv Hardware Maintenance Manual ...
Page 11: ...DANGER DANGER DANGER DANGER DANGER Chapter 1 Safety information 5 ...
Page 12: ...DANGER 6 Hardware Maintenance Manual ...
Page 13: ...PERIGO PERIGO PERIGO Chapter 1 Safety information 7 ...
Page 14: ...PERIGO PERIGO PERIGO PERIGO PERIGO DANGER 8 Hardware Maintenance Manual ...
Page 15: ...DANGER DANGER DANGER DANGER DANGER Chapter 1 Safety information 9 ...
Page 16: ...DANGER DANGER VORSICHT VORSICHT VORSICHT 10 Hardware Maintenance Manual ...
Page 17: ...VORSICHT VORSICHT VORSICHT VORSICHT VORSICHT Chapter 1 Safety information 11 ...
Page 18: ...12 Hardware Maintenance Manual ...
Page 19: ...Chapter 1 Safety information 13 ...
Page 20: ...14 Hardware Maintenance Manual ...
Page 21: ...Chapter 1 Safety information 15 ...
Page 22: ...16 Hardware Maintenance Manual ...
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Page 25: ...Chapter 1 Safety information 19 ...
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Page 27: ...Chapter 1 Safety information 21 ...
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Page 90: ...Overall 1 2 4 5 7 9 13 18 14 15 19 8 12 11 17 16 10 6 3 84 Hardware Maintenance Manual ...