JLG 120HX Service Manual - Manual (Page 71)

SECTION 2 - PROCEDURES
3120819 – JLG Lift – 2-49
13. Adjust HI trimpot until ammeter the value shown in
Table 2-4, Function Speeds.
14. Repeat step 13.
15. Place the creep toggle switch in the creep on posi-
tion. Adjust the mid trimpot to the value shown in
Table 2-4, Function Speeds.
16. Move controller handle back to the position given in
step 6 and check ammeter reading. This reading will
have changed due to HI trimpot adjustment, and
must be readjusted back to the value shown in Table
2-4, Function Speeds.
17. Move handle to the position given in step 13 and
check ammeter reading. This reading too will have
changed due to LO trimpot readjustment, and must
be adjusted back to the value shown in Table 2-4,
Function Speeds.
18. Move controller handle back to the position given in
step 6 and check ammeter reading. This reading will
have changed due to MID trimpot adjustment, and
must be readjusted back to the value shown in Table
2-4, Function Speeds.
19. Repeat steps 17 and 18 until LO and HI readings as
shown in Table 2-4, Function Speeds can be
achieved without further trimpot adjustments.
20. Adjust the Ramp trimpot 6 turns clockwise.
21. Release footswitch.
22. Connect ORANGE/RED (dump) wire to terminal strip
number 3 in platform console.
23. Using all applicable safety precautions, start
machine and allow hydraulic oil to reach a tempera-
ture of 100° F - 140° F (38° - 60° C).
24. Depress footswitch and operate controller until trail-
ing edge of slide lock is even with housing lock
notch. Hold control handle in that position.
25. Adjust LO trimpot until applicable function just starts
to work. Immediately stop adjustment.
26. Release footswitch and stop machine.
27. Seal each trimpot with a drop of enamel paint to pre-
vent maladjustment due to vibration.
TRIM Adjustment (S/N 38697 to Present)
NOTE: For the following procedure, disconnect the control-
lers at the following locations:
Flow Control Card: Terminal Strip 23 Red/Orn
wire (turn knob to obtain setting)
Lift Controller: Terminal Strip 27 Blk/Yel Wire
Swing Controller: Terminal Strip 24 Blu/Orn
wire
1. Perform the following checks with ignition power to
the platform, with the engine NOT running and the
controllers disconnected as outlined in the note
above.
2. Install ammeter capable of measuring from zero to 2
amps in series.
3. Position IGNITION/EMERGENCY STOP switch to
ON, but do not start engine.
4. Using a screwdriver, adjust the ramp trimpot coun-
terclockwise 25 turns or until the trimpot clicks.
5. Depress footswitch.
6. Operate controller until 1/2 of slide lock is out of the
housing lock notch. Hold control handle in that posi-
tion.
7. Check the mA reading in the opposite direction.
8. Operate the controller until 1/2 of the slide lock is out
of the housing lock notch. Hold the control handle in
that position. Check the mA reading.
9. Verify step 7 and step 8 mA readings are within 0.50
mA of each other. If the readings are within toler-
ance, proceed to step 11.
10. If the readings in step 9 were not within tolerance,
Loosen the setscrew located in the gear on the
potentiometer shaft of the controller. Using a screw-
driver, adjust the potentiometer very slightly in either
direction. Tighten the setscrew on the gear and
recheck for the proper mA readings. Repeat this
step until the proper adjustment is obtained.
11. Place the creep toggle switch in the off position.
12. Position the Controller as outlined in step 6. Using
correct size common blade screwdriver, adjust LO
trimpot until ammeter indicates the proper value as
shown in Table 2-6, Platform Controller Settings (S/N
38697 to Present). Clockwise rotation of trimpot
adjust screw increases ammeter; counterclockwise
rotation decreases ammeter reading.
13. Operate controller in the same direction as in step 6
to the full extent of its travel and hold handle in that
position.