JLG 120-SXJ ANSI Service Manual User Manual
Page 70
SECTION 4 - BOOM & PLATFORM
4-18
– JLG Lift –
3121105
4.9
BOOM LOAD RADIUS SETUP
PROCEDURES - 120SX
NOTE: The boom length and angle sensor adjustments
need to be made before the display lights are
adjusted.
The boom length and angle sensor is factory set and
does not normally require adjusting unless it is
removed from the base boom for maintenance.
Length Indicator Adjustment
1.
Level the frame before beginning any adjustments.
2.
Make all adjustments with the engine running unless
otherwise noted.
3.
Fully retract the boom.
4.
On the Load Radius Circuit Card, measure TP10 and
insure that 10 (+0.1/-0) Volts DC is present.
5.
On the Load Radius Circuit Card, adjust P1 to 1.233
Volts DC while measuring TP1.
6.
Make the following adjustment with the power off.
On the Load Radius Circuit Card, disconnect con-
nector J2 (the 6 pin connector on the printed circuit
board). Measure between Pin (6) of the socket on
the circuit board and ground (TB1-1), adjust potenti-
ometer P5 to a value of 1.915 (+/- 0.005) Ohms.
Reconnect J2 when adjustment is complete
7.
Turn the power on and measure TP2. It should be
1.287 Volts DC. Re-adjust the 5K Ohm potentiometer
in the boom cable reel if necessary. Adjust the 5K
Ohm potentiometer by loosening the three screws
holding it in place. Tighten the three (3) screws
when adjustment is complete.
Boom Angle Sensor Adjustment
1.
With the platform level, the boom fully retracted and
at 45 (+/- 1) degrees elevation, measure the DC
voltage at TP5 on the Load Radius Circuit Card.
2.
Loosen the three screws securing the sensor to the
box and rotate the sensor until 7.1 (+/- 0.1) Volts DC
is measured at TP5. Tighten the screws on the sen-
sor.
3.
Return the boom to horizontal.
Radius Adjustment and Display Lights
Setting Procedure
1.
On the Load Radius Circuit Card, measure TP11 and
adjust potentiometer P6 for a reading of 0.525 Volts
DC.
2.
On the Load Radius Circuit Card, measure TP8 and
adjust potentiometer P2 for a reading of 2.223 Volts
DC.
3.
On the Load Radius Circuit Card, measure TP9 and
adjust potentiometer P3 for a reading of 5.0 Volts
DC.
4.
Telescope the boom until the leading edge of the red
marking tape is exposed from the mid boom. Adjust
potentiometer P2 until the red light just turns on and
the blue light turns off.