68 DART NO CHARGE

My dart has stopped charging and I a lost. It was charging good one day and the next it has stopped, I had the alternator checked and it was found to be working as it should, so I replaced the regulator with a new electronic one and still no charge. The ammeter is working and shows discharge when lights are turned on with engine running so now I am lost. Any one have an idea as to what is going on? Any and all help is appreciated. Thanks DVO