Rectifier Diode / Bridge: Testing and Inspection

AR15.40-P-9301-02CW Test Alternator Diodes





Connection scheme

030 Engine tester with oscilloscope
065 DC clip-on probe

F32 Front prefuse
G1 On-board electrical system battery
G2 Generator
M1 Starter
W10 Right front battery ground point

1 Connect engine tester with oscilloscope (030).
2 Start engine
3 Switch on low beams

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

4 Assess diode harmonics at 3000 rpm (engine speed).





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





Example: Harmonics, if a positive diode is defective.





Example: Harmonics, if a minus diode is defective.