C.E. Niehoff & Co. C627/C628/C631/C656/C657/C658/C671/C680 Troubleshooting Guides - Manual (Page 4)

Page 4
TG30G
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.
2. Inspect all vehicle battery connections
Connections must be clean and tight.
3. Determine battery voltages and states 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+
terminal and black lead to alternator B– termi-
nal. Clamp inductive ammeter on B+ cable.
5. Operate vehicle
Observe charge voltage.
If charge voltage is above
16 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
increase 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 5, for A2-149 regulator or
Chart 2, page 6, for A2-155 regulator.
SYMPTOM ACTION
TABLE 1 – System Conditions
Low Voltage Output
High Voltage Output
No Voltage Output
Preliminary Check-out
Check symptoms in Table 1 and correct if necessary.
Identification Record
List the following for proper troubleshooting:
Alternator model number ______________________
Regulator model number _____________________
Setpoints listed on regulator ___________________
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CAUTION
Check: loose drive belt; low bat-
tery 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 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 or
regulator.
Check: lost residual magnetism
in self-energizing alternator.
A2-149 regulator: Chart 1
A2-155 regulator: Chart 2
Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wires
Section B: Basic Troubleshooting