Komatsu 830E-AC Shop Manual page 248

REGULATOR TESTING
Regulator Bypass Test (No Output)
If the Troubleshooting Alternator test procedure indi-
cates low or no output, perform the following test to
determine if the voltage regulator is defective or if the
alternator is defective.
1. A self-energized alternator may have lost its
magnetism.
a. Touch a steel tool to the shaft on the anti-
drive end to detect any magnetism.
b. If the shaft is magnetized, proceed to Step 5.
c. If the shaft is not magnetized, proceed to
Step 2.
2. If the shaft is not magnetized:
a. Momentarily (1 second), connect a jumper
wire from the regulator (D+) terminal to the
alternator (B+) terminal.
b. Touch the shaft with the steel tool to detect
significant magnetism.
c. If the shaft is magnetized, proceed to Step 5;
otherwise go to Step 3.
FIGURE 10-8. JUMPER WIRE CONNECTION
1. Plug
D10-18
2. Regulator
Battery Charging Alternator
3. If the shaft is still not magnetized, remove the
jumper from the alternator (D+) terminal on the
regulator and go to Step 4.
4. If the shaft is not magnetized:
a. If connected, unplug the alternator-to-regula-
tor wiring harness connection.
b. Install a jumper wire from the alternator (B+)
terminal to pin F in the wiring harness plug.
c. Momentarily (1 second), connect a jumper
wire from pin A to the alternator (B-) terminal.
d. Touch the shaft with the steel tool to detect
significant magnetism.
e. If the shaft is not magnetized, the alternator
is defective.
f. If the shaft is magnetized, the regulator is
defective.
FIGURE 10-9. WIRING HARNESS PLUG JUMPER
WIRE CONNECTION
1. Wiring Harness Plug
5. Connect a voltmeter across pin D and pin C in
the wiring harness plug. Does battery voltage
exist?
a. If no voltage, the alternator is defective.
b. If voltage is present, proceed to Step 6.
2. Regulator
D10003 07/06