Sounds like the condensor exploded.. It's very likely there is more damage elsewhere in that circuit, like in the ignition coil or in the magneto windings.. And there's a reason the condensor popped.. That could be anything but i'm thinking a shorted wire or a blown voltage regulator (if there is one). The weak spark you used to get but get no more might indicate that something in the circuit is now totally fried.
I would resign myself to doing a very thorough check of all the individual ignition components as well as the wiring harness, switches, fuses etc... This aint gonna be easy or quick. Hopefully you'll get lucky and find the source of the problem (and i don't think its the condensor.. I think that just died in the crossfire)
I know nothing about your bike so i can't be specific about any of it. Start with a wiring diagram so you can trace and examine the circuit and examine the individual components as best you can.. To prevent destroying replacement components, inspect the bike for wiring damage FIRST.. then replace components with known good ones and test for spark again.
Condensors should show no physical damage.. After removing it from the circuit, a continuity check will show zero ohms between it's wire and the metal can.
A ignition coil will have some measure of resistance.. probably a few ohms in the coils. (this doesn;t mean the coil is perfect.. only that it' not totally gone.)
The wire coils in the magneto should show no continuity between them and the frame. The coils of wire will show some continuity beween the wire ends but, like the ignition coil, that doesn't guarantee they are perfect.
None of the "hot" wires on the bike should show continuity to the engine block.