maggie SMG sounds dead

While the cover are off; Make certain the fuses are good, take an ohmmeter, and touch either probe to the negative speaker terminal, and the other probe to the capacitor lead on the HF panel side. If you have a reading there(around 6 Ohms and perhaps an audible response); the HF panel is good. If the panels and fuses are good; it could well be the electrolytics went bad somehow. Where are you located?

The change that the capacitors are gone is almost zero. Do you have some coloratians? Try to wipe the tweetersection with your fingers. I am sure that you find wire(-s) has/have broken. Need manufacturer support or buy a tweeterkit from Magnepan. (Replacing the original caps with polypropylene does miracles! )

You need to use an ohm meter to verify the tweeter wires have not broken. You sometimes can't see the breaks. Rotting tweeter wires is a common failure, with the old ones.