C.E. Niehoff & Co. C720 Troubleshooting Guides User Manual
Page 4
Page 4
TG0036A
Section C: Advanced Troubleshooting
If you have questions about your alternator or any of these test procedures, or if you need to locate a Factory Authorized Service Distributor, please contact us at:
C. E. Niehoff & Co.• 2021 Lee Street • Evanston, IL 60202 USA
TEL: 800.643.4633 USA and Canada • TEL: 847.866.6030 outside USA and Canada • FAX: 847.492.1242
E-mail us at [email protected]
Self-energized alternator may have lost magnetism. Touch steel tool
to shaft to detect any magnetism. Is shaft magnetized?
Momentarily (1 sec.) jumper DF (D+) terminal on alternator to
B+ terminal on alternator. Touch shaft with steel tool to detect
any magnetism. Is shaft magnetized?
Yes
No
Yes
No
Check for battery voltage across pins A and E on plug end of harness. Does voltage exist?
Disconnect battery cable to B+ terminal on alternator. Connect
red lead of DMM to pin B on plug end of harness. Connect black
lead to pin C on plug end of harness. Does continuity exist?
Yes
No
No
Alternator is defective.
Yes
Yes
No
Disconnect Adapter or jumper wires.
Alternator is defective.
Unplug alternator-to-regulator harness. Plug CEN Regulator Bypass Adapter A10-129 into harness plug. Clip
red lead to B+ terminal on alternator. Touch black lead to ground on alternator case. (If Adapter is not avail-
able, connect jumper wires from pin B on harness to alternator B+ terminal and from pin C on harness to
ground.) Spark will occur at ground. Touch steel tool to shaft to detect any magnetism. Is shaft magnetized?
Operate alternator. Does voltage output exist?
Yes
No
System operating normally.
Figure 3 –
Alternator-to-Regulator Harness Plug
PIN CONNECTIONS
Pin A
B–
Pin B
Field +
Pin C
Field –
Pin D
AC
Pin E
B+
Connect red lead of DMM to ground on alternator case.
Connect black lead to pin D on plug end of harness.
Does continuity exist?
No
Yes
Alternator is defective.
Regulator is defective.
Chart 1 – No Output
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Alternator is defective.
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