Someone dropped my HD681 superlux headphones. Causing something to rattle inside it. After opening it, I found that it was the permanent magnet that became detached and fell out. So I glued it back. The original glue seems to be dried up and no longer bonded to the plastic holder.

Here's step by step the disassembly and repair.

01

Take off the name plate. You can remove one small screw for the next time. Don't lose the screw!



You'll need to desolder the two wired in order to get into the unit.
Remove the one big main screw

Squeeze the plastic cage, until the pins retaining the cage comes out of the holes holding it.

Remove the cage and set it aside.



This is the permanent magnet.

Check if the voice coil is okay, no physical breaks, etc. Check the fine wires on the inside of the cups as well




Use like a wooden skewer to hold the magnet while glue is applied on the edge of the magnet to hold it in place.





Have fun!




Useful links:
http://rockgrotto.proboards.com/thread/4769/superlux-hd-681-modifications

Direct PDF steps to open the headphone
http://www.rock-grotto.co.uk/HD681.pdf