Since you mentioned points it's an older distributor, and likely an older coil, too. You might get lucky and find a carbon track or even a crack that has become a carbon track between that one pin in the distributor and the center, or to ground? Pull the cap and check inside with a bright light. While you're looking, check the condition of the eight electrodes around the inside, and the brass conductor on the end of the rotor. Jack's probably on target with the compression check, but I'd look at the distributor cap just in case....