TM-9-2350-311-20-2
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS
DECEMBER 1993
TM-9-2350-311-20-2 - Page 750 of 828
TM 9--2350--311--20--2
B--2
B--2
MAINTENANCE FUNCTIONS -- CONTINUED
g. Remove/Install.Toremoveandinstallthesameitemwhenrequiredtoperformserviceorothermaintenancefunctions.
Installmaybetheactofemplacing,seating,orfixingintopositionaspare,repairpart,ormodule(componentorassem-
bly) in a manner to allow the proper functioning of an equipment or system.
h. Replace.Toremoveanunserviceableitemandinstallaserviceablecounterpartinitsplace. “Replace”isauthorizedby
the MAC and assigned maintenance level is shown as the 3d position code of the SMR code.
i.
Repair. The application of maintenance services
1
including fault location/troubleshooting
2
, removal/installation and
disassembly/assemblyprocedures,andmaintenanceactions
4
toidentifytroubles andrestoreserviceabilitytoanitem
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/opera-
tional condition as required by maintenance standards in appropriate technical manuals (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. Consists of those services/actions necessary for the restoration of unserviceable equipment to a like new
conditioninaccordancewithoriginalmanufacturingstandards. Rebuildisthehighestdegreeofmaterielmaintenance
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.
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 mainte-
nance significant components, assemblies, subassemblies, and modules with the next higher assembly.
b. Column 2, Component/Assembly. Column 2 contains the item names of components, assemblies, subassemblies,
and modules for which maintenance is authorized. (* indicates item applies only to M109A2/M109A3 howitzers.) (***
indicatesitemappliesonlytoM109A4/M109A5howitzers.)Noasteriskindicatesitemiscommontoallvehicleconfigu-
rations.
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.)
1
Services -- Inspect, test, service, adjust, align, calibrate, and/or replace.
2
Fault location/troubleshooting -- The process of investigating and detecting the cause of equip-
ment malfunctioning; the act of isolating a fault within a system or unit under test (UUT).
3
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 main-
tenance under consideration (i.e., identified as maintenance significant.
4
Actions -- Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
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