Have you tried a temporary hot wire directly to the upstream side of the coil to see if you can isolate the open circuit to a specific area? It's about 5 minutes' worth of troubleshooting with a piece of primary wire that will narrow down the possibilities of where to look for the problem.
Jerry
Actually I have. Made up a jumper wire from a hot terminal on the voltage regulator to the (-) lead on the coil positive ground system. No spark. Jumper removed and there is full 6 volts at the (-) side of the coil with the ignition switch on. No spark. Ran through all the previously mentioned tests with the following results: coil wire has continuity. Ohm test between coil terminals with key off shows 0. Test between hot lead and coil center pegged the needle on my cheap tester. Points are opening and closing as they should. Tested for shorts in various components of the dizzy, no problems found. No problems found with the rotor or cap.
Odd thing is the truck was starting and running fine then one day no spark. Battery is good, ignition switch has not been left in the on position. Grounds are all clean and in the factory stock locations. As said I’m backing out and resetting.
Thanking everyone for the help.
