03-09-2019, 06:11 AM
To unglue the cone, try lacquer thinner or acetone, if it isn't coming apart already. I think that pressing out the pole piece will work, it does not look welded in like in some speakers, see if you can find an arbor or a hydraulic press to do the job, don't use a hammer and drift. Before you go that far though, see if it's just a broken wire near one end, you will have unwrap the field coil anyhow to rewind it.
Regards
Arran
Regards
Arran