SECTION 4 - BOOM & PLATFORM
3120746
– JLG Lift –
4-13
limit switch Functional Check
TO AVOID COLLISION AND INJURY IF PLATFORM DOES NOT
STOP WHEN A CONTROL SWITCH OR LEVER IS RELEASED,
REMOVE FOOT FROM FOOTSWITCH OR USE EMERGENCY STOP
TO STOP THE MACHINE.
1. Operate machine from ground control.
2. Check elevation limit switch as follows:
a. Lift boom up to 2 degrees to 7 degrees above
horizontal. The switch should activate at this
point.
b. Lift boom down to 2.5 degrees to 7.5 degrees
below horizontal. The switch should reset at
this point.
3. Check capacity limit switch as follows:
Boom Length Switch.
a. Raise boom to horizontal (place angle indica-
tor on base boom between boom pivot pin
and lift cylinder attach pin).
b. Telescope boom out until 500 lb. (230 kg)
light comes on (may need to used auxiliary
power to position boom correctly).
c. Mark wear pad location on the fly and mid
booms.
d. Telescope boom out to full extension.
e. Measure from the mark on the fly boom to the
wear pad and measure from mark on the mid
boom to the wear pad.
f. Add These two numbers together (they
should be approximately equal) they should
measure 137" to 139" (348 to 353 cm).
Boom Angle Switch.
a. Telescope boom to full extension.
b. Lift boom up until 1000 lb. (450 kg) light
comes on.
c. Lift boom down using auxiliary power until
500 lb. (230 kg) light comes on. Boom angle
must be 45 degrees to 50 degrees (place
angle indicator on base boom between boom
pivot pin and lift cylinder attach pin).
d. Lift boom up until 1000 lb. (450 kg) light
comes on. Boom angle should be 55 degrees
to 64 degrees.
NOTE: If limit switch settings need to be changed, you will
need to recheck that the 500 lb. (230 kg) light
comes on at 45 degrees to 50 degrees when lifting
down.
4. Check capacity limit switch as follows:
Main Boom Length Switch.
a. Lift main boom to approximately horizontal.
b. Telescope boom out until 500 lb. (230 kg)
light comes on (may need to used auxiliary
power to position boom correctly).
c. Mark the wear pad location on the main fly
boom.
d. Telescope the main boom to full extension.
e. Measure from the mark on the fly boom to the
wear pad. The dimension should be 125" to
127" (317.5 to 322.5 cm).
Main Boom Angle Switch.
a. Lift main boom to approximately horizontal.
b. Telescope boom out until 500 lb. (230 kg)
light comes on (may need to used auxiliary
power to position boom correctly).
c. Lift main boom up until 1000 lb. (450 kg) light
comes on. The boom angle at this point
should be 55 degrees to 60 degrees.
d. Lift main boom down until 500 lb. (230 kg)
light comes on. The boom angle at this point
should be 45 degrees to 50 degrees.
NOTE: If limit switch settings need to be changed, you will
need to recheck that the 500 lb. (230 kg) light
comes on at 45 degrees to 50 degrees when lifting
down.
5. Raise main boom, extend and retract telescope.
Check for delayed movement of fly section, indi-
cating loose cables.
6. Swing turntable to LEFT and RIGHT a minimum of
45 degrees. Check for smooth motion.
NOTE: Step 7 is only applicable for machines with an exter-
nal tilt sensor.
7. With the aid of an assistant to monitor the CHAS-
SIS OUT OF LEVEL indicator light on the platform
control console, manually activate the indicator
light by compressing any one of the three tilt indi-
cator mounting springs. If the light does not illumi-
nate, shut down machine and contact a qualified
service technician before continuing operation.
NOTE: Step 8 is applicable for machines with an internal tilt
sensor.
8. Check the chassis out of level indicator located on
the platform control console by driving, with the
machine in level position, up a suitable ramp of at
least 5° slope. Check the out of level indicator, with
the machine on the ramp. If the light does not illu-