Abnormal Waveforms
The size of the waveform patterns can differ greatly, depending on the adjustment of the variable knob on the oscilloscope. See Fig 1 .
Identification of abnormal waveforms is easier when there is a large output current (regulator is not operating). Waveforms can be observed when the headlights are illuminated.
Check the conditions of the generator malfunction light (illuminated/not illuminated) also, and carry out a total check.