I just replaced my alternator because my amp gage was showing discharge when I turned on the headlights. My new alternator is doing the same thing. It shows a discharge when the lights are engaged. I have a new battery and a somewhat new external voltage regulator. The alternator is only showing a little over 12 volts when running, and I would think it should show around 14 volts. When I turn the light on, the voltage drops to 11 volts. I could use some advise please. I have a 1968 TR-250. Nose wants to know what to try next.