flattop1
Dawg 89
Any of y'all ever do this test for bad diodes .
Chasing a parasitic drain .
Note: we set our meter to AC. We usually use DC when testing our car. By selecting AC, your meter will ignore the DC voltage and focus on AC. If AC is leaking out, your meter will see it. The diodes are supposed to block the AC from getting out of the alternator. If a diode goes bad it will let some of the AC get out. For the simple alternators in our classic cars, anything over 0.5 volts AC is too much. You will probably see a little AC. The diodes are not perfect, so a small amount of AC will always get out. Sensitive meter. Typically, it’s 0.010, 0.020, or 0.030 of a volt. Again, check with volt meter.
Chasing a parasitic drain .
Note: we set our meter to AC. We usually use DC when testing our car. By selecting AC, your meter will ignore the DC voltage and focus on AC. If AC is leaking out, your meter will see it. The diodes are supposed to block the AC from getting out of the alternator. If a diode goes bad it will let some of the AC get out. For the simple alternators in our classic cars, anything over 0.5 volts AC is too much. You will probably see a little AC. The diodes are not perfect, so a small amount of AC will always get out. Sensitive meter. Typically, it’s 0.010, 0.020, or 0.030 of a volt. Again, check with volt meter.