TM 1-1520-238-23
B-4
c. Service.
Operations required periodically to keep an item in proper operating condition, i.e., to clean (in-
cludes decontaminate, when required), to preserve, to drain, to paint, or to replenish fuel, lubricants, chemical fluids,
or gases.
d. Adjust.
To maintain or regulate, within prescribed limits, by bringing into proper or exact position, or by
setting the operating characteristics to specified parameters.
e. Align.
To adjust specified variable elements of an item to bring about optimum or desired performance.
f. Calibrate.
To determine and cause corrections to be made or to be adjusted on instruments or test, measur-
ing, and diagnostic equipments 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 placing, seating, or fixing into position a spare, repair part, or module (component
or assembly) in a manner to allow the proper functioning of equipment or a 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/installa-
tion and disassembly/assembly procedures,3 and maintenance actions4 to identify troubles and restore serviceabili-
ty 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) prescribed 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 like-new condition.
k. Rebuild.
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 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.
B.4.
EXPLANATION OF COLUMNS IN THE MAC, SECTION II.
a. Functional Groups (Columns 1 and 2).
The functional groupings shown in the sample below identify
maintenance significant components, assemblies, subassemblies, and modules with the next higher assembly.
1Services – Inspect, test, service, adjust, align, calibrate, and/or replace.
2Fault locate/troubleshoot – 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).
3Disassemble/assemble – Encompasses the step-by-step taking apart (or breakdown) of a spare/functional
group coded item to the lowest level of component identified as maintenance significant (i.e., assigned an SMR code)
for the level of maintenance under consideration.
4Actions – Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
