TM 5-3810-307-24-1-2
5a. ANTI-TWO BLOCK PROBLEM (SINGLE SWITCH)
PROBLEM: Function of Anti-Two Block System is faulty.
START
Check to see whether or not crane is in two-block condition.
Correct?
NO
Lower hook down into safe position.
YES
Turn power off or disconnect blue wire from X1:35 on connection board in central unit.
Refer to Drawings 2, 3, 14 in Section 10.
Next
Remove length cable core wire from terminal 1 in Boom Nose Junction Box.
Measure the resistance at the boom nose junction box between terminals 1 and 2 with
ohmmeter. This checks the function of the anti-two block switch.
Switch closed = 4700 500 Ohms (weight installed)
Switch open => 1 Megaohm (weight removed)
Refer to Drawing 2, 10 in Section 10.
Replace length cable core wire to terminal 1 in Boom Nose Junction Box.
Correct?
NO
Replace anti-two block switch.
YES
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G-12 Change-1