I suspect the rectifiers (diodes) are going bad in my alternator, what is the best way to check for this condition before removing from the airplane?
If you have access to an alternator test set, select “ripple voltage” and check. More commonly, you can check this by oscilloscope or a simple voltmeter. In either case, probe the output terminal on the alternator while running and look for less than one volt of AC. (If using a voltmeter, be sure you select the AC scale.) If you see more than one volt, this is most likely what you are hearing over the radio and the alternator should be repaired for bad or leaky diodes or replaced.
