JLG 150HAX Service Manual - Manual (Page 76)

SECTION 3 - CHASSIS & TURNTABLE
3-38 – JLG Lift – 3120817
3.12 PQ CONTROLLERS
TRIM Adjustment
1. Disconnect ORANGE/RED (dump) wire from appli-
cable terminal strip in platform console.
2. Install ammeter capable of measuring from zero to 2
amps in series with either valve coil B or D.
3. Position IGNITION/EMERGENCY STOP switch to
ON, but do not start engine.
4. Depress footswitch.
5. Operate controller until trailing edge of slide lock is
even with housing lock notch. Hold control handle in
that position.
6. Using correct size common blade screwdriver,
adjust LO trimpot until am-meter indicates 300 ma.
Clockwise rotation of trimpot adjust screw increases
ammeter; counterclockwise rotation decreases
ammeter reading.
7. Operate controller in the same direction as in step
(5) to the full extent of its travel and hold handle in
that position.
8. Adjust HI trimpot until ammeter indicates 500 ma.
9. Move controller handle back to the position given in
step (5) and check ammeter reading. This reading
will have changed due to HI trimpot adjustment, and
must be readjusted back to 300 ma.
10. Move handle to the position given in step (7) and
check ammeter reading. This reading too will have
changed due to LO trimpot readjustment, and must
be adjusted back to 500 ma.
11. Repeat steps (9) and (10) until LO and HI readings
of 300 ma and 500 ma can be achieved without fur-
ther trimpot adjustments.
12. Release footswitch.
13. Connect ORANGE/RED (dump) wire to applicable
terminal strip in platform console.
14. Using all applicable safety precautions, start
machine and allow hydraulic oil to reach a tempera-
ture of 100 to 140 degrees (38 to 60 degrees C).
15. Depress footswitch and operate controller until trail-
ing edge of slide lock is even with housing lock
notch. Hold control handle in that position.
16. Adjust LO trimpot until applicable function just starts
to work. Immediately stop adjustment.
17. Release footswitch and stop machine.
18. Seal each trimpot with a drop of enamel paint to pre-
vent maladjustment due to vibration.
19. Install controller and secure machine.
RAMP Adjustment
Controllers equipped with the RAMP feature actu-
ally compensate for abrupt control handle operation
by slowing the response time of the output signal
regardless of the speed with which the handle is
moved.
NOTE: It should be remembered that the ramp feature oper-
ates in both directions of the particular proportional
function. therefore adjusting the ramp potentiometer
to provide a delay in starting a function will provide a
corresponding delay in stopping that function.
1. Drive Controller.
a. Using all applicable safety precautions, start
machine and ensure that adequate space is
available to maneuver machine.
b. Position ENGINE SPEED switch to HIGH and
DRIVE SPEED switch to HIGH.
NOTE: Clockwise rotation of the ramp potentiometer adjust
screw increases ramp (delay) time; counterclockwise
rotation decreases ramp (delay) time.
c. Operate machine drive function and adjust ramp
pot so that machine will stop within 8 to 12 in.
(20 to 30 cm) when the control handle is
released from the full extent of its travel.
d. Operate machine drive function in the opposite
direction and check that stopping distance of 8
to 12 in. (20 to 30 cm) is maintained.