ARMY TM 9-6115-604-12
NAVY NAVFAC P-8-633-12
MAINTENANCE OF CRANK CYCLE TIMER M7 AND CRANK RELAY K3 . The crank cycle timer puts the
engine through four consecutive start cycles whenever the MASTER SWITCH is set to RUN If the engine fails to crank
after four consecutive crank cycles, the crank cycle timer opens crank relay K3, to prevent any further attempts at
cranking, and lights the EXCESSIVE CRANKING indicator on the annunciator alarm panel. After the EXCESSIVE
CRANKING indicator has been reset, the MASTER SWITCH may be set to RUN and the cranking process will be
Perform a functional test of the crank cycle timer M7 by operating the generator set.
Test crank relay K3 by applying 24 V dc to the solenoid and observing proper operation.
Disconnect battery power.
Tag and disconnect wiring from defective component.
Remove screws, nuts, and washers, and remove relay.
Install new relay and secure with screws, nuts, and washers.
Reconnect battery power.
MAINTENANCE OF WIRING HARNESS . The function of the wiring harnesses is to provide electrical continuity
between all electrical components associated with generator operation.
To avoid death or injury to personnel, no electrical component will be worked on
while energized. Ensure equipment is "tagged out" in accordance with Chapter 1,
Section III, of this manual and equipment is NOT energized. Residual voltage is
present at the generator leads with the regulator turned off, reaching SEVERAL
HUNDRED VOLTS on the generator set. Proper insulation and isolation of
metering equipment must be observed when testing this generator. USE PROPER
TEST EQUIPMENT TO CHECK FOR VOLTAGE before proceeding with work.
Disconnect battery power
Test. Where there is indication that a given harness is causing a malfunction, test the wires relating to the
malfunctioning circuit both for continuity and internal shorts. Check all suspect wires for continuity. Refer
to FO-4 through FO-12.
Splicing. Expose damaged wires by cutting harness sleeving as necessary, being careful not to cut
the insulation of serviceable wires when cutting the sleeving. It is normally most efficient to guide
the tip of the cutting instrument between parallel wires in the harness. The cuts In the sleeving
should always be made parallel with the harness assembly When the wires to be spliced are
exposed, proceed as follows
To avoid Injury to personnel, do not breathe fumes generated by soldering. Eye
protection is required. Remove rings and watches while soldering.
(a) Install shrink-down sleeve PO-135 of adequate length and diameter to cover finished splice,
over one end of broken or cut wire. Position shrink-down sleeve far enough from break so that it
will not interfere with splicing or soldering operations.