TM 9-4940-568-34
2-23
Table 2-7. Crane Troubleshooting (CONT).
(1) Using TELE control lever, retract
boom completely if not already done
(TM 9-4940-568-10).
(a) If test unit does not indicate 7.3
ft (2.2 m), go to Step (2) below.
(b) If test unit indicates 7.3 ft (2.2 m),
go to Step (5) below.
(2) Loosen screw on gear assembly and
slide gear assembly away from idler
gear being careful not to move gears
in relation to each other.
(3) Rotate gear assembly gear to the right
to increase test unit reading or to the
left to decrease test unit reading.
Moving the gear one to two teeth in a
particular direction will increase or
decrease test unit reading 0.1 to 0.2 ft
(.03 to .06 m).
(4) Mesh gear assembly gear and idler
gear and tighten screw when test unit
indicates 7.3 ft (2.2 m).
(a) If it is not possible to adjust
gear assembly enough that test
unit indicates 7.3 ft (2.2 m),
replace OSS box (Para 3-27).
(b) If test unit indicates 7.3 ft (2.2 m),
go to Step (5) below.
(5) Using TELE control lever, extend
boom completely.
(a) If test unit does not indicate 18.4
ft (5.61 m), go to Step (6) below.
(b) If test unit does indicate 18.4 ft
(5.61 m) go to Step 5 of this
Fault.
(6) Adjust length trimpot until test
unit indicates 18.4 ft (5.61 m).
(a) If it is not possible to adjust
length trim pot enough that test
unit indicates 18.4 ft (5.61 m),
replace OSS box (Para 3-27).
(b) If test unit indicates 18.4 ft
(5.61 m), go to Step (7) below.
(7) Repeat Steps (1) through (6) a
maximum of two more times to
achieve a consistent reading of 7.3
ft (2.2 m) (retracted) and 18.4 ft
(5.61 m) (extended) without needing
adjustment.
Continued on next page.
ADJUSTMENT TEST
Remove all jewelry such as rings, dog tags, bracelets, etc. If jewelry or tools contact positive electrical
circuits a direct short may result. Damage to equipment, injury or death to personnel may result.
Do not stand under crane. Mechanical failure and operator error can cause injury or death to personnel.
Record any adjustment made to gear assembly
and length trimpot. The number of gear teeth
moved or turns of trimpot screw may be
necessary information for later steps.
Adjustment made in Step (3) may be
affected by adjustment made in Step (6).
NOTE
BOOM
TELESCOPE
CONTROL LEVER
