TM 9-4940-568-34
2-16
Table 2-7. Crane Troubleshooting.
1. OVERLOAD SHUTDOWN SYSTEM (OSS) DISABLES CRANE FUNCTIONS,
BOOM UP, BOOM DOWN, TELESCOPE OUT AND HOIST UP.
INITIAL SETUP
START
Tools and Special Tools
Tool Kit, General Mechanic’s
(Item 67, Appendix F)
OSS Tester (Item 89, Appendix F)
Materials/Parts
Cable Ties (2) (Item 5, Appendix B)
Sealing Compound (Item 41, Appendix B)
Wire, Nonelectrical (Item 42, Appendix B)
Packing, Preformed (4) (Item 86, Appendix E)
References
TM 9-4940-568-10
1.
Do functions operate with top
overload shutdown (OSS) box
connector disconnected and
junction box terminals 1 and
19 jumpered together?
Go to Step 4 of this
Fault.
YES
NO
Hoist lowers.
Boom telescopes in.
Crane swings.
OSS box out of calibration.
OSS box faulty.
Tension load cell faulty.
Harness faulty.
Wire faulty.
KNOWN INFO
POSSIBLE PROBLEMS
TEST OPTIONS
REASON FOR QUESTION
Operation test.
If OSS box or tension load cell
is faulty, functions will operate
with OSS box disconnected. If
wiring from OSS box to OSS
function lockout valves is
shorted, functions will continue
not to work with OSS box
disconnected.
WARNING
Read WARNING
on Page 2-17
