Sick Sennheiser HD 595s

I have a pair of  these Senns which I managed to drop on a hard floor, ever since there has a been a resonance in one channel on certain low notes as if something has come loose and is vibrating, a bit like a buzzing sound.

Has anyone any idea about taking these to bits to see if anything has come loose and is repairable, or do I just bin them and look at getting some others, I do like these as they are very comfortable and are used mainly for watching TV late at night...........