Check Diodes of Generator

Connection diagram

G1 Battery
G2 Generator
W10 Battery ground
X4/10 Terminal block terminal 30/30U
030 Engine tester with oscilloscope
065 DC clamp-on probe


NOTE: It is not possible to assess the exciter diode when performing this test.

Engine tester with oscilloscope (030)
connect, disconnect.

Engine
start, switch off.

Low beam
switch on, switch off.

Diode harmonics
assess at 3000 rpm (engine speed).

Diode harmonics in order
renew regulator.

Diode harmonics not in order
renew generator.






Harmonics of diodes in order (voltage peaks possible but of no significance) (example).






Harmonics if positive diode is faulty (example).






Harmonics if negative diode is faulty (example).

NOTE: If problems exist with current supply, test diode matrix.


Commercially available testers
Engine tester with oscilloscope e.g. Hermann, Datascope 980
Bosch, MOT 301/400
Sun, 2110
BEAR, DACE