Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or by setting the oper-
ating characteristics to specified parameters.
Align. To adjust specified variable elements of an item to bring about optimum or desired performance.
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
Remove/Install. To remove and install the same item when required to perform service or other maintenance func-
tions. Install may be the act of emplacing, seating, or fixing into position a spare, repair part, or module (compo-
nent or assembly) in a manner to allow the proper functioning of an equipment or system.
Paint (ammunition only). To prepare and spray color coats of paint so that the ammunition can be identified and
protected. The color indicating primary use is applied, preferably, to the entire exterior surface as the background
color of the item. Other markings are to be repainted as original so as to retain proper ammunition identification.
Replace. To remove an unserviceable item and install a serviceable counterpart in its place "Replace" is autho-
rized by the MAC and assigned maintenance level is shown as the third position code of the Source, Maintenance
and Recoverability (SMR) code.
10. 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.
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 case 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
11. Overhaul. That maintenance effort (service/action) prescribed to restore an item to a completely serviceable/oper-
ational condition as required by maintenance standards in appropriate technical publications. Overhaul is nor-
mally the highest degree of maintenance performed by the Army. Overhaul des not normally return an item to like
12. 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 material mainte-
nance applied to Army equipment. The rebuild operation includes the act of returning to zero those age measure-
ments (e.g., hours/miles) considered in classifying Army equipment/components.
Explanation of Columns in the MAC
Column (1) Group Number. Column (1) lists Functional Group Code (FGC) numbers, the purpose of which is to identify
maintenance significant components, assemblies, subassemblies, and modules with the Next Higher Assembly (NHA).