TM 5-6350-264-14&P-9 NAVELEX EE 181-AA-OMI-100/E121 DZ-204 T.O.  31S9-2FSS9-1-9 j. Overhaul.      That   maintenance   effort   (service/ actions)  necessary  to  restore  an  item  to  a  completely serviceable/operational condition as prescribed by maintenance    standards    (i.e.,    DMWR)    in    appropriate technical publications.    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  (hours/miles,  etc.)  considered in classifying Army equipments/components. B-3. COLUMN ENTRIES. a. Column   1,   Group   Number.      Column   1   lists group   numbers,   the   purpose   of   which   is   to   identify components,  assemblies,  subassemblies,  and  modules with the next higher assembly. b. Column  2,  Component/Assembly.    Column  2 contains the names of components, assemblies, subassemblies,  and  modules  for  which  maintenance  is authorized. c. Column  3,  Maintenance  Function.    Column  3 lists  the  functions  to  be  performed  on  the  item  listed  in column 2. d. Column   4,   Maintenance   Level.      Column   4 specifies,  by  the  listing  of  a  "work  time"  figure  in  the appropriate subcolumn(s), the lowest level of maintenance authorized to perform the function listed  in column 3.This figure represents the active time required to   perform   the   maintenance   function   at   the   indicated level of maintenance.  If the number or complexity of the tasks   within   the   listed   maintenance   function   varies   at different   maintenance   levels,   appropriate   "work   time" figures  will  be  shown  for  each  level.    The  number  of man-hours specified by the "work time" figure represents the average time required to restore an item (assembly, subassembly, component, module,  end item, or system) to  a  serviceable  condition  under  typical  field  operating conditions.          This     time     includes     preparation     time, troubleshooting time, and quality assurance/quality control  time  in  addition  to  the  time  required  to  perform the     specific tasks identified for the maintenance functions authorized in the maintenance allocation chart. The  symbol  designations  for   the   various   maintenance levels are as follows: C....................... Operator or crew O ...................... Organization maintenance F ....................... Direct support  maintenance H....................... General support maintenance D....................... Depot maintenance e. Column  5,  Tools  and  Equipment.    Column  5 specifies,    by    code,    those    common    tool    sets    (not individual   tools)   and   special   tools,   test,   and   support equipment required to perform the designated function. f. Column  6,   Remarks.      Column  6  contains  an alphabetic code which leads to the remark in section IV, Remarks,   which   is   pertinent   to   the   item   opposite   the particular code. B-2