HOISTS 999 SERVICE/MAINTENANCE MANUAL
5-8
Published 05-16-17, Control # 233-03
Disconnecting Block-Up Limit Controls
Shorting plug (SP1, View A, Figure 5-6) is provided on the
left front corner of the rotating bed so the block-up limit
controls can be disconnected for the following reasons:
• Crane setup and rigging
• Maintenance
• Operations not requiring use of a block-up limit control
(clamshell and drag-line)
To disconnect the block-up limit controls, proceed as follows
(see Figure 5-6
):
1. Disconnect electric cable (C1, View B) from electric
cable (C2).
2. Connect shorting plug (SP1, View A) to electric cable
(C1).
3. Connect closure cap to electric cable (C2).
4. Reverse the steps to reconnect the block-up limit
controls.
Removing Jib or Boom Point
The junction boxes on the boom and jib points are equipped
with shorting plugs as shown in View C, Figure 5-6
.
When an attachment is removed, the electric cable from the
corresponding limit switch must be disconnected from the
junction box receptacle (View C, Figure 5-6
) and the proper
shorting plug connected to the receptacle.
Failing to perform this step will prevent the load drum from
hoisting and the boom from lowering. Also the operating limit
alert will come on.
Disconnect shorting plug and reconnect electric cable to
proper receptacle on junction box when corresponding
attachment is reinstalled.
Always connect closure caps to shorting plugs or ends of
cables when they are not in use.
NOTE: Each junction box has a decal identifying what
circuit each receptacle applies to. If in doubt, see
the wiring diagrams in Boom Wiring, Limits, and
Load Indicator Electrical Assembly drawing in the
999 Operator Manual.
A848
Cable
Cable
Brackets
Cable
Luffing Jib Butt
(typical top view)
Boom Butt
(top view)
FIGURE 5-5
Fixed Jib Butt
(typical view)
Cable Reel
Cable Reel
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