My next step would be to use a test light or voltmeter to verify:
1) Key on, points closed, 12v across the two coil low tension terminals.
2) Key on, points open, 0v across the two coil low tension terminals.
If these two voltages are not found, then there is a problem in the low tension side; maybe the switch isn't wired right; or the points aren't. Check between the hot terminal & ground, if no 12v then the switch or wiring is the problem. If the point terminal is always at ground, or always at 12v, the points are wired wrong (or possibly had some sort of coating on the contact faces; or maybe the wire is broken internally, etc.).
However, if the low tension voltage goes up & down as it should, then the problem is the coil itself, or on the high tension side. My next step would be to test for spark directly at the top of the coil to ground. If no spark, try a different coil.