General  descriptions 
The  desciptions  in  this  chapter  apply  to  any  ThinkPad 
model  that  has  the  PC-Doctor
®
 
DOS  diagnostics  program. 
Some  descriptions  might  not  apply  to  your  particular 
computer. 
Read  this  first 
Before  you  go  to  the  checkout  guide,  be  sure  to  read  this 
section. 
 
 
Important  notes 
v  Only  certified  trained  personnel  should 
service  the  computer. 
v  Before  replacing  any  FRU,  read  the  entire 
page  on  removing  and  replacing  FRUs. 
v  When  you  replace  FRUs,  use  new 
nylon-coated  screws. 
v  Be  extremely  careful  during  such  write 
operations  as  copying,  saving,  or  formatting. 
Drives  in  the  computer  that  you  are  servicing 
sequence  might  have  been  altered.  If  you  select 
an  incorrect  drive,  data  or  programs  might  be 
overwritten. 
v  Replace  an  FRU  only  with  another  FRU  of  the 
correct  model.  When  you  replace  a  FRU,  make 
sure  that  the  model  of  the  machine  and  the  FRU 
part  number  are  correct  by  referring  to  the  FRU 
parts  list. 
v  A  FRU  should  not  be  replaced  because  of  a 
single,  unreproducible  failure.  Single  failures 
can  occur  for  a  variety  of  reasons  that  have 
nothing  to  do  with  a  hardware  defect,  such  as 
cosmic  radiation,  electrostatic  discharge,  or 
software  errors.  Consider  replacing  a  FRU  only 
when  a  problem  recurs.  If  you  suspect  that  a 
FRU  is  defective,  clear  the  error  log  and  run  the 
test  again.  If  the  error  does  not  recur,  do  not 
replace  the  FRU. 
v  Be  careful  not  to  replace  a  nondefective  FRU.
What  to  do  first 
When  you  do  return  a  FRU,  you  must  include  the  following 
information  in  the  parts  exchange  form  or  parts  return  form 
that  you  attach  to  it: 
__  1.  Name  and  phone  number  of  servicer 
 
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