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 84 of 828
TM 9–2350–311–20–2
Change 1
2–23
Table 2-2.
PREVENTIVE MAINTENANCE CHECKS AND SERVICES FOR M109 SELF-
PROPELLED HOWITZER
Location
Item
No.
Interval
Item to Check/Service
Procedure
Not Fully Mission
Capable if:
1
Quarterly
Mount M145/M145A1
Check synchronization (para 18–4).
2
Quarterly
a. M117/M117A2
Telescope
Purge quarterly (TM 750–116). Purge im-
mediately if moisture is found in units be-
fore quarterly service date.
WARNING
The M1A1 collimator is radioactively illuminated. Check for presence of illumination and dam-
age. If discovered broken, damaged, or defective, follow the procedures listed on page b.
b. M1A1 Collimator
c. M118A2/M118A3
Elbow Telescope
d. M15 Elevation Quadrant
WARNING
The M140 alinement device is radioactively illuminated. Check for loss of luminescence, break-
age, damage, or defects. If present, follow the procedures on page b.
e. M140 Alinement
Device
f. M42 Tank Periscope
WARNING
3
Quarterly
Fire Control Instruments
Failure to aline reticle of M140 aline-
ment device with reticles of
M117/M117A2 panoramic telescope
and M118A2/M118A3 elbow telescope
using boresighting procedure could
result in projectiles landing outside tar-
get area. Injury or death of friendly
forces can result from firing with
misalined fire control equipment.
Perform boresighting on target board,
alining reticles of M117/M117A2 panoram-
ic telescope and M118A2/M118A3 elbow
telescope on test target board. Next, in-
stall the M140 alinement device in front of
each sighting and fire control instrument
(M117/M117A2 panoramic telescope and
M118A2/M118A3 elbow telescope) to en-
sure that reticle of the M140 alinement
device coincides with the reticles of the
M117/M117A2 panoramic telescope. This
check must be performed to ensure accu-
racy of the M140 alinement device
(TM 9–2350–311–10).
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