JLG 1250AJP Service Manual - Manual (Page 492)

SECTION 6 - JLG CONTROL SYSTEM
6-60 – JLG Lift – 3121171
Telescope tower out to max length
2. After pressing the ENTER key , the analyzer
will display “CHECKING BOOM…” and capture the
position of the Tower Length. The control system will
then, Keep the PVG command at zero leave the
Main Control and PVG enable valves off and Turn On
the Tower Telescope Enable valve and monitor the
Tower Telescope length for decreasing movement of
more than 0.5" (1.27 cm) for 60 seconds. If this
occurs the test will abort and display on the top line
“CHECK FAILED:” and “TOWER TELE HOLD” on
the bottom line. After the 60 seconds has elapsed
the control system will leave the Enable valve on and
turn on the Main Control Valve and monitor the
Tower Telescope length for decreasing movement of
more than 0.5" (1.27 cm) for 60 seconds. If this
occurs the test will abort and display on the top line
“CHECK FAILED:” and “TOWER TELE APU” on the
bottom line.
3. If the “CHECK BOOM…” test passes the analyzer
will display “CALIBRATING…”on the bottom line and
record tower extended length 1 (upper) and tower
extended length 2 (lower). The tower extended
length will be set at 669.4”. The length 1 sensor and
the length 2 sensor must be in the proper range or
“CAL FAILED” and “TWR LEN1 FAULT” or “TWR
LEN2 FAULT” will be displayed. The precise tower
transport length switch trip point will be verified to be
4.0”+3.5”/-1.5”, otherwise the analyzer will display
“CAL FAILED” and “TWR L SW FAULT”.
Step 6 - Position 6
1. After completing the previous step, the analyzer will
read: