National Crane Published 5-27-2018 Control # 039-06 5-41
800D SERVICE
5. At the hoist mount end, reach into the rear of the boom
and loosen the capscrew on the anti-two-block cable
clamp enough to let the cable run around it with minimal
effort. This clamp is located on the extend cable anchor.
6. Disassemble spade bolt anchor attaching anti-two-block
wire to the extend cable plate on the hoist mount end of
the boom.
7. Pull wire from hoist mount end. Replacement wire
“temporary splice” may need assistance reeving around
anti-two-block cable clamp in rear of 3rd section. If
excessive force is needed to pull wire through, observe
wire routing and make adjustments as needed to avoid
breaking “temporary splice”. If splice fails at this point,
wire routing Alternative No. 2 should be used.
8. Pull wire through boom, leaving enough wire on sheave
case end to properly attach and terminate wire.
9. Tighten anti-two-block wire clamp located in rear of 3rd
section.
10. Route sheave case end of anti-two-block wire around
clamp in sheave case, and through holes in side plates.
Pulling on this end will tension the static length of anti-
two-block wire clamped in the 3rd. Approximately 15-25
lb (6-11 kg) will be sufficient to provide proper operation.
Tighten sheave case anti-two-block wire clamp.
11. Reassemble quick disconnect plug to anti-two-block
wire. Proper wire attachment is critical for proper anti-
two-block system operation. Consult electrical
schematic in this book for proper connector wiring.
12. Temporary splice” should now be approximately 10 ft (3
m) past the hoist mount end of the boom. Break “splice”
and slide strain relief/cord grip onto wire into
approximate position inside the boom.
13. Assemble spring and spade bolt to cord grip and
reassemble anchor components to extend cable anchor
plate on the hoist mount. Slide cord grip up anti-two-
block wire into boom to increase spring tension on
moving length of anti-two-block wire. Approximately 2 in
(50 mm) of spring extension tension should be adequate
for proper operation.
14. Visually inspect interior routing of anti-two-block wire for
excess slack in wire, inaccurate routing of wire, etc.
Correct any problems before boom operation.
Alternative No. 2
This procedure is to be used for anti-two-block wire
replacement in the event of a complete separation of the
wire, or the inability to access one or both of the ends outside
the boom assembly. This procedure routes a new anti-two-
block wire through the boom without having an existing wire
to pull it through (Alternative No. 1).
Special tools or equipment:
•Electrical tape
•Installation tool
To route the wire the entire length of the boom, a long tube,
to be used as an installation tool, must be utilized to transport
the end of the anti-two-block wire from one end of the boom
assembly to the other. A telescopic grease applicator for the
boom, hydraulic tubing or electrical conduit are all
possibilities for an installation tool. The installation tool
should be at a minimum 2 ft (0,5 m) longer than the retracted
boom assembly.
1. Retract boom completely.
2. Loosen and remove anti-two-block cable clamp
arrangements from sheave case and 3rd section extend
anchor. Remove spade bolt anchor from extend cable
anchor plate in the hoist mount end of boom.
3. Remove quick disconnect plug on anti-two-block wire by
unscrewing base of plug and disconnecting individual
wires from connections. Note pigtail length at this time,
and wire/terminal number location for proper
reassembly.
4. Pull anti-two-block wire out of boom assembly. Visually
inspect boom interior from both ends to verify alt the
cable has been removed from the boom. Visually
inspect center sheave on extend cylinder for damage.
5. Start installation of replacement wire on the sheave case
end of the boom assembly. Using electrical tape, attach
one end of replacement wire to the end of the installation
tool.
6. Insert installation tool and wire into sheave case in the
center open area between the sheave case side plates.
Visually guide the wire and installation tool over the
center sheave on the extend cylinder sheave case.
7. Push installation tool and wire through boom until it
appears at the hoist mount end, detach wire from
installation tool, route wire through open top of hoist
mount and temporarily tie off to a convenient anchor
point. Pull installation tool out sheave case end of boom.
8. From sheave case end of boom, attach other end of
replacement wire to installation tool with electrical tape.
Insert installation tool and wire into the boom sheave
case, in the open area between the sheave case side
plates. Visually guide this end under the center sheave
on the extend cylinder sheave case.
9. Push installation tool and wire through boom until it
appears at the hoist mount end. Do not detach wire from
installation tool.
10. From hoist mount end of boom, locate installation tool
and attached wire, and pull the wire out of the boom
section, removing the slack loop from the sheave case
end of the boom. This will place the wire close to, if not
on, the center sheave of the extend cylinder.
Fo
r
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