ARMY TM 9-2815-257-24 AIR FORCE TO 38G1-128-2 MARINE CORPS TM 10155A/2815-24/3 B-2 f.     Calibrate.  To determine and cause corrections to be made or to be adjusted on instruments or test, measuring,  and  diagnostic  equipment  used  in  precision  measurement.    Consists  of  comparisons  of  two instruments, one of which is a certified standard of known accuracy, to detect and adjust any discrepancy in the accuracy of the instrument being compared. g.    Remove/Install.    To  remove  and  install  the  same  item  when  required  to  perform  service  or  other maintenance functions.  Install may be the act of emplacing, seating, or fixing into position a spare, repair part, or module (component or assembly) in a manner to allow the proper functioning of an equipment or system. h.    Replace.  To remove an unserviceable item and install a serviceable counterpart in its place.  "Replace" is authorized by the MAC and assigned maintenance level is shown as the 3rd position code of the SMR code. i.     Repair.      The   application   of   maintenance   services(1)   including   fault   location/troubleshooting(2), removal/installation, and disassembly/assembly(3) procedures, and maintenance actions(4) to identify troubles and  restore  serviceability  to  an  item  by  correcting  specific  damage,  fault,  malfunction,  or  failure  in  a  parts, subassembly, module (component or assembly), end item, or system. j.     Overhaul.    That  maintenance  effort  (service/action)  prescribed  to  restore  and  item  to  a  completely serviceable/operational  condition  as  required  by  maintenance  standards  in  appropriate  technical  publications (i.e.,  DMWR).   Overhaul  is  normally  the  highest  degree  of  maintenance  performed  by  the  Army.  Overhaul does not normally return an item to like new condition. k.    Rebuild.  Consists of those services/actions necessary for the restoration of unserviceable equipment to a  like  new  condition  in  accordance  with  original  manufacturing  standards.   Rebuild  is  the  highest degree of materiel maintenance applied to Army equipment.  The rebuild operation includes the act of returning to zero those age measurements (e.g., hours/miles) considered in classifying Army equipment/components. B-3.  Explanation of Columns in the MAC, Section II. a.    Column 1, Group Number.  Column 1 lists functional group code numbers, the purpose of which is to identify  maintenance  significant  components,  assemblies,  subassemblies,  and  modules  with  the  next  higher assembly. b.    Column  2,  Component/Assembly.    Column  2  contains  the  item  names  of  components,  assemblies, subassemblies, and modules for which maintenance is authorized. (1) Services  -  Inspect, test, service, adjust, align, calibrate, and/or replace. (2)  Fault  location/troubleshooting    -    The  process  of  investigating  and  detecting  the  cause  of  equipment malfunctioning; the act of isolating a fault within a system or unit under test (UUT). (3) Disassembly/assembly  -  The step-by-step breakdown (taking apart) of a spare/functional group coded item  to  the  level  of  its  least  component,  that  is  assigned  an  SMR  code  for  the  level  of  maintenance  under consideration (i.e., identified as maintenance significant). (4) Actions  -  Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.