Check Generator Diodes- Ar15.40-S-9301-02E

AR15.40-S-9301-02E	Check generator diodes
	Risk of accident  by starting up automatically while the engine is running. Risk of injury  from bruises and burns when intervening during the starting process or while the engine is running.	Secure the vehicle against starting by itself. Wear closed, close-fitting work clothing. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A

Type 907 with Motor 274, 642, 651 

1. Attach the DC clamp (065) of the engine tester with oscilloscope (030) to the positive lead of the on-board power supply battery (G1) according to the connection diagram.
2. Start the motor.
3. Switch on low beam.

   An assessment of the excitation diodes is not possible with this test.

4. Assess the diode ripple at an engine speed of 3000 RPM.
5. Switch off the engine after completing the test.
6. Remove the DC current clamp (065) of the motor tester with oscilloscope (030).

Shown without defect 

The harmonic ripple of the diodes is okay (example). Voltage peaks are possible, but of no significance.

Shown plus diode is defective 

One of the plus diodes is defective (example).

The negative diode shown is defective 

One of the minus diodes is defective (example).