Point arcing is why the condenser is in place. In any other application it would be called a capacitor(just a hangover from early days). The condenser acts like a sponge. Any sudden change in voltage, gets "absorbed" in the condenser as an electrical charge. When the value of the condenser is too small, material is pulled from one point face to the other(I used to know if it went plus to ground but part timers has taken that bit for a ride). If the value is too big the material is pulled the other way. We used to at one time play with "capacitive discharge" systems and this was how to decide on how big the condenser we needed. Any way to get to your issue, the condenser has failed. Change it and the points should last much longer. Yes, some new ones are bad(common complaint) but they are cheap. You did admit to a ballast resistor, and a previous post pointed out that resistors fail "open". That would be no spark so get the condensor and it should fix the problem.
