General descriptionsThis chapter includes descriptions for any ThinkPad modelthat has the PC-Doctor DOS diagnostics program. Somedescriptions might not apply to your particular computer.Read this firstBefore you go to the checkout guide, be sure to read thissection.Important notesv Only certified trained personnel shouldservice the computer.v Read the entire FRU removal and replacementpage before replacing any FRU.v Use new nylon-coated screws when youreplace FRUs.v Be extremely careful during such writeoperations as copying, saving, or formatting.Drives in the computer that you are servicingsequence might have been altered. If you selectan incorrect drive, data or programs might beoverwritten.v Replace FRUs only for the correct model.When you replace a FRU, make sure the modelof the machine and the FRU part number arecorrect by referring to the FRU parts list.v A FRU should not be replaced because of asingle, unreproducible failure. Single failurescan occur for a variety of reasons that havenothing to do with a hardware defect, such ascosmic radiation, electrostatic discharge, orsoftware errors. Consider replacing a FRU onlywhen a problem recurs. If you suspect that aFRU is defective, clear the error log and run thetest again. If the error does not recur, do notreplace the FRU.v Be careful not to replace a nondefective FRU.What to do firstWhen you do return a FRU, you must include the followinginformation in the parts exchange form or parts return formthat you attach to it:__ 1. Name and phone number of servicer__ 2. Date of service__ 3. Date on which the machine failed© Copyright IBM Corp. 2004 25
