Leaving the ignition on is most likely to damage the coil.
Second to that is the points my be burned.
It is extremely unlikely to have had any ill effect on the capacitor.
With power on see if you have 12volts on teh live side of teh coil.(if not you have blown a fuse somewhere) Then check the breaker side to a good earth. There should be less than half a volt across the points ( providing they are closed). To check that the points are not welded together turn the motor over slowly, at some point you should see 12 volts on the breaker side of the points.
If this all looks good most likely problem is the insulation in the HT winding has broken down. Swap coils and if the fault moves with the coil you know what to do
