TM 9-1220-238-14
Table 3-3. Troubleshooting (Mechanical)
Item
No.
Malfunction
Probable cause
Corrective action
1
Frame assembly rotates
a. Broken or weak
a. Replace spring
with brake on.
brake lever.
b. Worn or missing
b. Replace brake shoe,
brake shoe.
c. Crank damaged.
c. Replace crank,
2
Frame assembly binds.
a. Improper assembly of
a. Remove frame assembly
frame and/or spindle
spindle and re-seat frame.
b. Roller assembly or
b. Replace roller assembly
assemblies, malfunction.
3
Plotting disk surface
Surface damage or beyond
Turn disk over or replace
precludes functional
serviceable life limit.
Accuracy.
4
Scale assembly scrapes
a. Improper thumbscrew
a. Adjust thumbscrew. Para 2-3b
disk surface.
Adjustment.
b. Bent, scale or links.
b. Replace scale assembly
Para 2-3 and d,
5
Scale assembly cannot be
a. Disk, plotting and
a. Adjust and orient
be oriented.
vernier scales out of
Para 3-13c, d, and e
adjustment.
b. Arm assembly bent
b. Replace scale assembly
or damaged.
c. Bearing eccentrics out
c. Adjust eccentrics
of adjustment.
6
Vernier knob falls to
a. Brake components worn
a. Replace worn or damaged
orient frame assembly.
or damaged.
b. Broken or missing pin
b. Replace missing pin
in shaft, sleeve or
Knob.
c. Setscrew loose or
c. Tighten or replace
missing from slide.
d. Shaft bent.
d. Replace shaft
7
Brace assembly binds In
a. Bent tubes or sleeves
a. Replace brace or
stowed or operational
in brace or damaged
support assembly
position.
leg sockets In support
Assembly.
b Cracked or defective
b. Replace defective parts
welding.
-8
Support loose or unstable.
a. Damaged or missing
a. Replace wing screws
wing screws.
b. Leg foot plates bent
b. Replace leg
or defective welding.
9
Unable to secure brackets
Thumbscrews broken bent,
Replace thumbscrews Para 4-14, fig B-3,
to support assembly.
or missing.
3-8
