Sometimes the spring on the points is shorting, the normal current path TO GROUND is from the wiring terminal where the condensor and the wire from coil (via the distributors side pass thru insulated bushing) is attached, then when points are closed to the distributor case/frame ground. Make sure all the little wires from condensor,,,,,,,to coil via pass thru,,,,are good and not shorted, then be sure when the points are open THERES NO TO GROUND PATH from the little wiring terminal. Both the coil wire and condensor are only grounded out when the points are closed. The condensor, to straight DC, should show an open circuit to ground ya know otherise its bad/shorted out.
With IGN ON, put a DC test lamp on the coils output (or where dist side terminal is) and with engine slowly turned over, it should be ON when points are open but OFF when closed
As already posted the cap and rotor tip needs to be in correct time with the cap so when the coil fires the tip is lined up with the correct cap pickup/terminal. The coils fires when the points break open and at that time the rotor tip needs to be lined up with the right cap pickup.