JLG 1500SJ Operator Manual - Manual (Page 147)

SECTION 5 - LCD DISPLAY PANEL - GENERATION 1 & 2
3121261 – JLG Lift – 5-51
Jib Locked
When the boom control system senses jib is locked ONLY for the
first time, the display will show the Jib Locked image on the
machine status tray for 3 seconds.
The display will show a different image on the machine status
tray after 3 seconds have elapsed.
Figure 5-36. Jib Locked Screen