Caution – C.E. Niehoff & Co. C653/C653A/C625 Troubleshooting Guides User Manual
Page 5
Page 5
TG13G
Section C: A2-146/A2-153 Advanced Troubleshooting
A2-146/A2-153 REGULATOR – THIS PAGE ONLY
Self-energized alternator may have lost magnetism. Touch steel tool
to shaft to detect any magnetism. Is shaft magnetized?
Momentarily (1 sec.) jumper D+ terminal on regula-
tor to B+ terminal on alternator. Touch shaft with
steel tool to detect significant magnetism. Is shaft
magnetized?
Yes
No
Yes
No
Figure 6 – Alternator-to-Regulator Harness Plug
Chart 1 – No Output
Install a jumper from B+ terminal on alternator to
pin F in harness plug. Momentarily (1 sec.) jumper
pin A to B– terminal on alternator. Touch shaft with
steel tool to detect significant magnetism. Is shaft
magnetized?
Yes
No
PIN CONNECTIONS
Pin A
F–
Pin B
Phase
Pin C
B–
Pin D
B+
Pin E
D+
Pin
F
F+
Set DMM to diode test. Connect black lead of DMM
to pin E in harness plug. Connect red lead to B+
terminal on alternator. DMM should read OL. Reverse
leads. DMM should also read OL.
Unplug alternator-to-regulator harness. Connect
DMM across pin D and pin C in harness plug.
Does battery voltage exist?
Yes
No
Alternator is defective.
Yes
No
Alternator is defective.
Alternator is defective.
Regulator is defective.
Install a jumper from B+ terminal on alternator to
pin F in harness plug. Momentarily (1 sec.) jumper
pin A to B– terminal on alternator. Touch shaft with
steel tool to detect significant magnetism. Is shaft
magnetized?
Yes
No
Alternator is defective.
Regulator is defective.
Remove jumper from D+ to B+.
When conducting this step,
ensure that the probes do not
touch other pins, as an arc
may damage the wiring in the
harness.
CAUTION