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:
vThey maintain tight connections.
vThey do not easily come loose, even with shock or
vibration.
vThey are harder to tighten.
vThey should be used only once.
Do the following when you service this machine:
vKeep the screw kit (for the P/N, see “Miscellaneous
parts”on page167) in your tool bag.
vAlways use new screws.
vUse a torque screwdriver if you have one.
Tightenscrews as follows:
vPlastic to plastic
Turnan additional 90 degrees after the screw head
touches the surface of the plastic part:

90degrees more

(Cross-section)

vLogic card to plastic
Turnan additional 180 degrees after the screw head
touches the surface of the logic card:

180degrees more

(Cross-section)

vTorquedriver
If you have a torque driver,refer to the “Torque”column
for each step.
FRUreplacement notices
56 ThinkPad T20, T21, T22, T23 (MT 2647/2648)