ARMY TM 5-5420-212-23
MARINE CORPS TM 08676A-23/3
i. Repair. The application of maintenance services1, including fault location/troubleshooting2, removal/installation,
and disassembly/assembly3 procedures, and maintenance actions4 to identify troubles and restore serviceability to an
item by correcting specific damage, fault, malfunction, or failure in a part, subassembly, module (component or
assembly), end item, or system.
j. Overhaul. That maintenance effort (service/action) necessary to restore an 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 a 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 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. End item
group number shall be "00".
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
(for detailed explanation of these functions, see paragraph B-2)
d. Column 4, Maintenance Category. Column 4 specifies, by the listing of a work time figure in the appropriate
subcolumn(s),the category 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 category of maintenance. If the number or
complexity of the tasks within the listed maintenance function vary at different maintenance categories, appropriate work
time figures will be shown for each category. 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 (including any necessary disassembly/assembly times),
troubleshooting/fault location time and quality assurance/quality control time in addition to the time required to perform
the specific task identified for the maintenance functions authorized in the maintenance allocation chart. The symbol
designations for the various maintenance categories are as follows:
Operator or Crew
Direct Support Maintenance
1 Services inspect, test, service, adjust, align, calibrate, and/or replace.
2 Fault locate/troubleshoot -The process of investigating and detecting the cause of equipment malfunctioning; the act of
isolating a fault within a system or a unit under test (UUT).
3 Disassemble/assemble-encompasses the step-by-step taking apart (or breakdown) of a spare/functional group coded
item to the level of its least componency identified as a maintenance significant (i.e., assigned an SMR code) for the
category of maintenance under consideration.
4 Actions welding, grinding, riveting, straightening, facing, remachinery, and/or resurfacing.