I hope I can get a bit of advice, not for one of my portable devices but for a speaker, in one of my Celestion Ditton 662 speakers one of the passive bass radiators (a 12" bass speaker without a magnet or coil) has failed. At the back of the cone there is a metal cylinder, also in the corrugated fabric diaphragm (the spider?) that supports the rear of the cone there is another metal cylinder. These are supposed to be glued together but the glue has given up, so the two metal cylinders are rattling against each other, link to video:
A good question. I tried using Copydex to fit some new surrounds and ended up buying new speakers. I think a large part of the problem with repairs is that (especially with the surrounds) you don't have the same access as when everything is being glued together at the same time.
I suppose it could be worse, being a passive unit there is no coil or magnet to worry about, although with 160 watts RMS these can move a long way so good glue is required, I managed to buy a couple of the powered bass speakers off EBay for these speakers, they fitted in the holes and are doing a great job so I am not stuck. I would like to repair and refit the passives though, they must resonate at a slightly different frequency because of the weight and drag of the coils.