The old brown box ignitions are just that, very old and should be replaced. 10 years or more. Even if you repair the cap and wire the odds are that ignition won't last much longer, if it continues to work at all.

You could replace with another fixed advance position or replace with an auto advance. The auto advance only requires the engine have the sensor locked in a 28* BTDC position relative to the hub magnet. A hole or two is drilled in the timing ring and threaded to accept a set screw. The set screw locks the ring in place at the 28* position. Plug in the ignition and fly. The instructions that Jody would provide are quite explanatory and simple to accomplish, If you can read and use an electric drill you can handle the operation.

To re-use the old, old ignition puts that Nosen at risk when it fails. It will fail. Electrical components have an aging factor that should not be ignored.