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IdeaPad Y450 Hardware Maintenance Manual
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 IdeaPad 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 (for the P/N, see
•
“Miscellaneous parts” on page 98) 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° 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.
