Pertronix Ignitor 111 troubleshooting
Did you check for 12V WHEN CRANKING? That is a different circuit.
Not much to check......
Pull the cap and check the insides, for dirt, junk, wear, rubbing, physical damage. Make sure the distributor is actually turning with the starter
You MAY be able to check the ignitor somewhat, do you have a tach? Does it show RPM when cranking? Try a test lamp on the coil NEG. Crank and see if it blinks on/ off or bright/ dim. That would suggest coil not ignitior
After that it's a tossup........try a different coil or different ignitor, whichever is cheaper/ easier