TROUBLESHOOTING & REPAIR
F-48 F-48
RANGER 305D
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FLASHING VOLTAGETEST (continued)
TEST PROCEDURE
1. Perform the Case Cover Removal
Procedure.
2. Make sure that the battery is fully charged
and in good condition, and the battery con-
nections are clean and tight.
3. Remove lead #229 from the oil pressure
switch; see wiring diagram and Figure #1.
Insulate or position the lead so it cannot
come in contact with chassis ground or any
other wiring. See Figure F.11.
NOTE: Disconnecting lead #229 bypass the oil-
pressure switch and simulates a running engine.
NOTE: The oil pressure switch is located on the
left side of engine just above the oil filter. See
Figure #1.
4. Place the RUN/STOP switch in the “RUN”
position. (The engine protection light should
remain off.)
5. Connect the voltmeter probes to brush
terminals. Seewiringdiagramandfigure
#2.
6. Measure the voltage; it should read about 3
to 5 VDC.
7. Set the RUN/STOP switch to the “STOP”
position.
8. If the meter reads normal voltage of 3 to
5 VDC, this test is complete.
9. If the meter reading indicates battery volt-
age, about 12 to 14 VDC, The rotor may be
open, or the brushes may be faulty or not
making proper contact with the slip rings.
10. Perform the Rotor Resistance Test.
Perform the Brush and Slip Ring Service
Procedure.
11. If the voltage measures zero or very near
zero; this condition could be caused by a
poor connection or a defective component in
the flashing circuit, or a shorted rotor wind-
ing.
12. Perform the Rotor Resistance Test.
11. Refer to the wiring diagram, pull plug P-2
from the control PC board and inspect each
terminal. Make sure that all terminals both
on the board and in the plug are clean and
in good condition, and that the pins are
securely crimped to the flex leads. Perform
the following additional test.
13. Switch the RUN/STOP switch to the “RUN”
position.
14. Use a voltmeter to check for the presents of
about 12VDC, battery voltage, at the follow-
ing locations on the control PC board.
(-) Lead #5K (P2-3) to (+) Lead #210H (P2-7)
(-) Lead #5K (P2-3) to (+) Lead #224B (P2-9)
(-) Lead #5K (P2-3) to (+) Lead #200N (P2-1)
NOTE: Lead #210H supplies 12VDC battery
voltage to the control PC board whenever the
run/stop switch is in the run position.
Lead #200N supplies DC flashing voltage from
the control PC board to the positive slip ring
through the R3 resistor.
15. If battery voltage is preset at all of the
above points; check the top grounding
stud on inside left case from and lead
#5H, also check leads #200, #200N, and
the 25 Ohms flashing resistor, R3. Make
sure all terminals are crimped tightly to
the flex leads and arc free of corrosion.