H1663:  2635 MOD 380 / 385 SYSTEM NOISE.                                     
                                                                                
                                                                                
                                                                                
                                                                                
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 The 2635 ThinkPad has a cooling fan that is thermostaticly                     
 controlled.  During normal operation the fan will cycle on and                 
 off.  This whirling sound is similar to the sound a Hard File                  
 produces.  Suspect this if the symptom is an intermittent HDD                  
 noise with no orange "Drive in use" system status indicator on.                
                                                                                
 Fan noise coming from the area of the fan duct at the rear                     
 of the system is normal.  Do not replace FRUs.