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  the 
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  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  243)  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  
66  T40/T40p,  T41/T41p,  T42/T42p