Lenovo ThinkPad A21e TP A21e, A22e Hardware Maintenance Manual (June 2001) - Page 57

FRU replacement notices, Screw notices, degrees more, Cross-

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FRU replacement notices FRU replacement notices This section contains 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 IBM ThinkPad computer, 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 They 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 131) 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. ThinkPad A21e, A22e, i 1800 53

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FRU replacement notices
This section contains 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 IBM
ThinkPad computer, 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
They 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 131) 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.
FRU replacement notices
ThinkPad A21e, A22e, i 1800
53