C.E. Niehoff & Co. N1233 Troubleshooting Guides - Manual (Page 3)

Page 3
TG0021A
Section 2: Basic Troubleshooting
D. Basic Troubleshooting
1. Inspect charging system components for
damage
Check connections at B– cable, B+ cable, and
alternator-to-regulator harness. Repair or
replace any damaged component before trouble-
shooting.
SYMPTOM ACTION
TABLE 1 – System Conditions
Check: loose drive belt; low
battery state of charge.
Check: current load on system
is greater than alternator can
produce.
Check: defective wiring or poor
ground path; low regulator
setpoint.
Check: defective alternator and/
or regulator.
Check: wrong regulator.
Check: high regulator setpoint.
Check: defective regulator.
Check: alternator.
Check: broken drive belt.
Check: battery voltage at alter-
nator output terminal.
Check: defective alternator
and/or regulator.
Check: lost residual magnetism
in self-energizing alternator.
Go to Chart 1, page 4.
Low Voltage Output
High Voltage Output
No Voltage Output
C. Preliminary Check-out
Check symptoms in Table 1 and correct if necessary.
A . Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wires
B. Identification Record
List the following for proper troubleshooting:
Alternator model number ____________________
Regulator model number _____________________
Setpoints listed on regulator __________________
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CAUTION
2. Inspect all vehicle battery connections
Connections must be clean and tight.
3. Determine battery voltage and state of charge
If batteries are discharged, recharge or replace
batteries as necessary. Electrical system cannot
be properly tested unless batteries are charged
95% or higher. In addition, open circuit voltages
must be within ± 0.2 V.
4. Connect meters to alternator
Connect red lead of DMM to alternator B+ ter-
minal and black lead to alternator B– terminal.
Clamp inductive ammeter on B+ cable.
5. Operate vehicle
Observe charge voltage.
If charge voltage is above
33 volts, immediately
shut down system. Electrical system damage may occur if
charging system is allowed to operate at high voltage. Go to
Table 1 at left.
If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.
6. Observe charge volts and amps
Charge voltage should increase and charge amps
should decrease. If charge voltage does not in-
crease within ten minutes, continue to next step.
7. Batteries are considered fully charged if charge
voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.
8. If charging system is not performing properly,
go to Chart 1, page 4.
9. Check OVCO circuit
Shut down vehicle and restart engine. If alterna-
tor functions normally after restart, a “no output
condition” was a normal response of voltage
regulator to “high voltage” condition. Inspect
condition of electrical system, including loose
battery cables, both positive and negative. If
battery disconnects from system, it could cause
“high voltage” condition in electrical system,
causing OVCO circuit to trip.
If you have reset alternator once, and electrical
system returns to normal charge voltage condi-
tion, there may have been a one time, high volt-
age spike, causing OVCO circuit to trip.
If OVCO circuit repeats cutout a second time in
short succession and shuts off alternator F+
circuit, try third restart. If OVCO circuit repeats
cutout, go to Chart 2, page 5.