TM 9-1220-238-14
upon a moment's notice
protective gloves to prevent cracking of the skin,
irritation and/or inflammation.
(3)
The utilization of diesel fuel, gasoline or
3-13. Adjustment and Orientation
benzine (benzol) for cleaning IS prohibited.
a. General. The following procedures may be used
by organizational personnel in whole or In part to adjust
3-12. Preventive Maintenance by Operator.
and orient the vernier bracket assembly, plotting disk
and scale assembly. Eccentric Bearings of the scale
a. Purpose To assure maximum operational
assembly should not be disturbed unless absolutely
readiness, it is necessary that the equipment be
necessary and all other adjustments have failed.
systematically inspected at intervals each day it is
b. Clamp board plotting screws (Fig. B-1, 25, and
operated. Any deficiencies discovered that cannot be
33).
corrected by replacing parts, will be reported on DA
(1)
Check board plotting assembly for
Form 2404
stability and proper installation of brace and leg
(1)
Exercise care when handling the board
assemblies (2) Be certain wingscrews are not damaged,
plotting, and associated equipment. Do not knock
seat properly and assure stability of the assembly during
against or drop on hard surfaces which may cause
operation.
inaccuracy, damage or improper functioning of
c. Vernier Bracket Assembly (fig 1-1)
equipment.
(1) Rotate vernier knob clockwise to stop Rotate
(2)
Unnecessary turning of screws or other
knob counterclockwise to opposite stop and count
parts not incident to the functioning of the equipment is
number of turns required Rotate knob clockwise on half
forbidden.
the number of turns counted to the center of the vernier
(3)
Stops are provided to limit the travel of
movement.
certain components. Do not attempt to force movement
(2) Loosen two mounting screws holding vernier
or rotation of any control beyond the stop limit.
(4)
Keep the equipment as clean and dry as
screws are approximately centered in the elongated
possible, especially before storing or placing it within a
holes. Tighten screws.
container or case
(3) Press and hold the brake lever on the vernier
(5)
When not in use, keep equipment
bracket assembly and rotate the frame assembly so that
covered and in the carrying chest provided to protect
the zero index on the azimuth scale is aligned with the
against dust, moisture, weather and general
zero index on the vernier scale Release the brake lever.
d. Plotting Disk (fig. 1-1).
(6)
To prevent excessive damage and wear
(1) Loosen the six adjusting screws around the
of threads, never tighten beyond a snug fit or the
edge of the plotting disk and center the screws in the
capable limits thereof.
elongated holes of the disk.
(7)
Equipment that cannot be adjusted or
(2) Tighten the six screws.
corrected by the authorized procedure must be referred
to the responsible personnel.
(1) Tighten thumbscrew and locking nut at the
c. Preventive Maintenance Checks and Services.
anchor point of the scale assembly on either bracket
assembly finger tight Refer to Figures 2-1 and 2-2 for
maintenance checks and services which will be
familiarization and location of referenced components
performed at the designated intervals and will apply to
during this procedure.
operator/crew
and
organizational
maintenance
(2) Position scale assembly so that elbow ring is
personnel who will use, stow, package or ship the
just off edge of disk and that eccentric components on
equipment.
under side of ring are exposed.
d. Daily Preventive Maintenance. Each piece of
(3) Move lower connecting links and scale to
equipment will be inspected each day it is operated.
upper right of board and close to an engraved line on
This service is divided into three parts as indicated In (1)
plotting disk.
through (3) below.
(4) Rotate the frame with the vernier knob until
(1)
Before operation service. This is a brief
line and scale edge are parallel.
service to ascertain that the equipment is ready for
(5) Move lower connecting links and scale to lower
operation It is primarily a check to see if conditions
left of the plotting disk (6) If scale straightedge is not
affecting the equipment's readiness have changed since
parallel with an engraved line on the plotting disk within
the last after operation service.
1/64 of an inch, notify direct support personnel to adjust
(2)
During operation service. This service
consists of detecting unsatisfactory performance.
(3)
After operation service. This is basic
daily service for the equipment. It consists of correcting,
inso far as possible, any operating deficiencies. The
board plotting M18 should be prepared to operate
3-3
