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

Connection diagram shown for model 230 

Fig 1: Identifying Alternator Diodes Connection Diagram

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1. Connect engine tester with oscilloscope (030) with current clamp (065) according to the connection diagram.
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)

Fig 2: Identifying Diode Harmonics In Order (Screen Display)

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Example: Zero line, if the alternator fuse is defective.

Fig 3: Zero Line (Screen Display)

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Example: Harmonics, if a positive diode is defective.

Fig 4: Harmonics Positive Diode Is Defective (Screen Display)

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Example: Harmonics, if a minus diode is defective.

Fig 5: Harmonics Minus Diode Is Defective (Screen Display)

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