TM 9-4520-271-14
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INTRODUCTION
Continued
6.
Calibrate. To determine and cause corrections to be made or to be adjusted on instruments of 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.
7.
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.
8.
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 third position code of the Source, Maintenance and
Recoverability (SMR) code.
9.
Repair. The application of maintenance services, including fault location/troubleshooting, removal/installation,
disassembly/assembly procedures, and maintenance actions 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.
NOTE
The following definitions are applicable to the "repair" maintenance function:
Services Inspect, test, service, adjust, align, calibrate, and/or replace.
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).
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).
Actions Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
10. Overhaul. That maintenance effort (service/action) prescribed to restore an item to a completely serviceable/
operational condition as required by maintenance standards 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.
11. 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.
Explanation of Columns in the MAC
Column (1) Group Number. Column (1) lists FGC numbers, the purpose of which is to identify maintenance significant
components, assemblies, subassemblies, and modules with the Next Higher Assembly (NHA).
Column (2) Component/Assembly. Column (2) contains the item names of components, assemblies, subassemblies,
and modules for which maintenance is authorized.
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