M977 and M985 Operating Procedures (Cont)
2-18. M977, M985 CRANE OPERATION (MANUAL CONTROLS) (CONT).
Keep hook block at least 2 ft (0.61 m) from end of boom.
If hook block hits end of boom it may damage cable or
hook block and crane will lose power. Wait 6 seconds
for power to return and check crane for damage.
When crane is overloaded, M977 and M985 overload
systems will automatically shut off power to telescope
boom out, raise boom, or hoist load any higher. The
M977 overload system will also prevent lowering
boom. Overload condition can be corrected by
lowering load to ground or other supporting surface
by using hoist control level only.
When telescoping the boom, the TELESCOPE and
HOIST control levers should be operated at the same
Crane movement from one lever may be slower than
the other when operating two levers together.
Move TELESCOPE control lever (3) to OUT position to extend
boom (2) and move HOIST control lever (4) to DOWN position to pay
out cable (5).