Section
4-8 LX 31/41 Work Platform
Maintenance
4.6
4.6 Switch Adjustments
PROPORTIONAL CONTROL
ADJUSTMENT (Figure 4-8)
When required by the following procedure, lay out a
twenty foot course, on level ground, free from potholes
or other obstructions. Mark a starting line and finish line
visible from the platform of the machine.
Potentiometers are sealed to protect sensitive adjust-
ments from vibrations, or from tampering. Remove
sealant prior to adjustment, and replace after.
Use a small screwdriver or special adjustment tool to set
adjustment pots. Pots can be easily damaged.
Pots have 15 turns of adjustment, more than one turn
will often be required to complete the adjustment. If
pots have been previously set, reset by turning no more
than 1 turn at a time. If they have not been previously
set, preset to about mid range and start from there.
Turn pot clockwise (CW) to increase settings.
Turn pot counterclockwise (CCW) to decrease settings.
Adjust pots only in sequence as outlined in this procedure.
Procedure
1. Lower machine fully to insure that controller is in
high speed range.
2. Turn Ramp Trimpot fully counterclockwise until a
click is heard with each revolution.
3. Push Control Handle slightly forward, just enough to
illuminate the red L.E.D. on the P.C.B.
4. Adjust the Threshold Trimpot so that the machine
just begins to move.
5. Push the Control Handle fully forward and drive the
machine over the 20 foot course.
Figure 4-9: Platform Down Limit Switch
Note: Do not steer the wheels during speed test,
insure that the front wheels are straight prior to this
operation. Allow the machine to rise to full speed,
and mark time from second that the Front Wheels
cross the starting line, until the second that the Front
Wheels cross the finish line.
6. Adjust the Hi Trimpot to the proper high speed
found in Table 5-1.
7. Elevate the platform enough to put the machine into
low speed range.
8. Push the Control Handle fully forward and drive the
machine over the 20 foot course.
9. Adjust the Lo Trimpot to the proper low speed
found in Table 5-1.
10. Lower the machine fully and turn the Ramp Trimpot
8 to 10 turns clockwise. Adjust for smooth accelera-
tion.
11. Recheck speeds to insure proper adjustment. Reset
as necessary.
PLATFORM DOWN LIMIT
SWITCHES (Figure 4-9)
The Platform Down Switches close the circuit to the
Cutout Relay, (R15), bypassing the Tilt Sensor when the
platform is lowered; and to the Platform Down Relay,
(R16), which provides power to the Drive Relay, Propor-
tional Controller high speed circuit, and Series/Parallel
Relay (R5).
Figure 4-8: Proportional Controller
Low Range Pot
Ramp Pot
High Range Pot
Threshold Pot
Limit Switches
Switch Mounting Bracket
Magnets
Capscrews
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