Rectifier Diode / Bridge: Testing and Inspection

AR15.40-P-9301-02V Test alternator diodes

Connection scheme:

In this test it is not possible to assess the exciter diodes.

1 Connect engine tester with oscilloscope (030).
2 Start engine.
3 Switch on low beams.
4 Assess diode harmonics at 3000 rpm (engine speed).

Example: Diode harmonics in order (voltage spikes possible, but not significant):

Example: Diode harmonics in order (voltage spikes possible, but not significant)

Example: Zero line if the starter, alternator fuse (in wiring harness) (F56) is defective:

Example: Zero line if the starter, alternator fuse (in wiring harness) (F56) is defective.

Example: Harmonics, if a positive diode is defective:

Example: Harmonics, if a positive diode is defective.

Example: Harmonics, if a minus diode is defective:

Example: Harmonics, if a minus diode is defective.