TM 10-3950-672-10
k. Two-block Indicator. The two-block (ALARM) indicator (40) is in a panel located above the main control panel.
The indicator is a red ALARM light that illuminates when the antitwo-block switch is actuated, indicating a two
block condition. A BUZZER also sounds when the light illuminates. Refer to paragraph 4-2q for a more detailed
description of the antitwo-block system operation.
l. Two-block Lockout Override. The two-block lockout override (BY-PASS) switch (41) is a two-position keyed
switch placarded NORMAL and OVERRIDE and is located to the right of the ALARM indicator light. With the
switch in NORMAL, two-block lockout will occur. With the switch in OVERRIDE, the lockout solenoid valve is
energized to open the valve and allow two-block lockout override.
m. Backup Alarm. (Not shown) The backup alarm is an audible alarm used to warn personnel when the crane is
backing up. The backup alarm system is electrical and consists of the backup alarm and associated wiring. The
alarm is connected into the backup light electrical wiring, and is activated when the backup light is used. The
backup alarm is installed on the right rear side of the frame.
n. Park Brake Indicator. The PARK BRAKE indicator (38) is located on the left side of the main control panel. A
pushbutton micro-switch located on the park brake lever lights the indicator if the park brake is engaged.
5-2.
PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS).
5-2.1
General.
a. Before you operate. Always keep in mind the CAUTIONS and WARNINGS.
Perform your before (B) PMCS.
b. While you operate. Always keep in mind the CAUTIONS and WARNINGS.
Perform your during (D) PMCS.
c. After you operate. Be sure to perform your after (A) PMCS.
d. If your equipment fails to operate. Troubleshoot with the proper equipment.
Report any deficiencies using the proper forms. See TM 38-750.
5-2.2
Procedure.
PMCS procedures in the table are intended to insure that the crane is ready to be operated safely with minimum
crane wear and tear.
The PMCS table lists the checks and services that need to be performed at various intervals. The intervals were
determined by crane design and expected use.
a. "Before" or (B) PMCS shall be performed by the operator prior to starting the engine and attempting to operate
the crane.
5-8
