JLG 1250AJP Service Manual - Manual (Page 491)

SECTION 6 - JLG CONTROL SYSTEM
3121171 – JLG Lift – 6-59
the enable valves on and turn on the Main Control
Valve and turn on the Tower Lift PVG valve at a 20%
down command and monitor the Main Lift angle for
decreasing movement of more than 0.2 deg, Tower
Lift angle for decreasing movement of more than 0.2
deg and Tower Telescope length decreasing move-
ment of more than 0.5" (1.27 cm) for 60 seconds. If
one of these conditions occur the test will abort and
display on the top line “CHECK FAILED:” and “MAIN
LIFT APU”, “TOWER LIFT APU” or “TOWER TELE
APU” on the bottom line depending on which sec-
tion moved.
4. If the “CHECKING BOOM…” test passes then Tower
Lift Up will be enabled and the analyzer will read:
The Control System will disable all functions except
auto platform level and tower lift up.
5. After the pressing the ENTER key , the ana-
lyzer will display “CALIBRATING…”on the bottom
line and Control System will record left tower angle
4, right tower angle 4, and high cylinder angle. The
Control system establishes the high tower angle cal-
ibration point per sensor by taking the difference
between the angle 4 and the ground slope in the
direction of the boom. High Tower Angle Calibration
value = 80.0 (77.0 on old cylinder stroke towers) +/-
Ground Slope. The high cylinder angle will be set to
81.7. The cylinder angle reading must be within the
proper range or “CAL FAILED” and “CYL ANGL
FAULT” will be displayed.
Step 5 - Position 5
1. After completing the previous step, the analyzer will
read:
The Control System will disable all functions except
auto platform level and tower tele out. The Control
System will energize tower lift up with the tower tele
out command. The analyzer will display “CAL
FAILED” and “TWR NOT UP” if movement of the cyl-
inder angle sensor is detected. The Control System
will monitor and record the tower length sensor
reading at which the tower transport length switch
changes state. The analyzer will display “CAL
FAILED” and “TWR LEN FAULT” if the switch does
not change state by 4”+/-3”.