Looking at the pic, I don't THINK the camring has jumped out judging from the fact it's still pretty flush with the housing. The ring is located by a screw-in pin which engages with a notch and said pin should be in said notch.
The spring looks close to the lower lobe of the cam, at about half past five in the pic - but the spring's arc also looks as close as can be to its smallest judging from the amount of 'tail' extending beyond the securing ear where the little screw is. Probably OK - but worth making quite sure that it isn't touching there or on the opposite, upper, ramp of the camring, because if it does it's a definite reason for a problem.
All 'K series' mags have camrings rather than a central cam. The system works fine as a rule, especially on mags like yours with a fixed camring.
The condenser is indeed on the inside as mentioned, in a recess at the drive end of the armature next to the coil. About the most awkward place it could be! It is wired between the 'nut' at the bottom of the centre screw that holds the cb unit on (low tension 'live') and the body of the magneto ('earth'), so in parallel with the contact breaker, which is what we need. It is unlikely that anything has happened to it that would kill all sparks all of a sudden though - usually they deteriorate and you get misfiring, pitted points, and poor starting when hot, which gets progressively worse.
Might be worth checking that when the points are 'closed' they really ARE closed and making good contact. It's delicate with a meter, but if you have a sensitive one you want to see 0 ohms across the points, shut, and about 0.5 ohms across them, open. That half ohm is the resistance of the primary winding of the coil, so it's not like measuring across the points on a battery & coil ignition system where you'll see 'Open Line' when they're open. Also worth checking that the brush or brass strip in the cb end cover (for stopping the engine) isn't touching anything except the head of the centre screw.
