I did open them, but I did not find anything. I was concerned about doing it myself for 2 reasons. The first being that the plastic clamps holding the driver in place are very tight, and I am very worried that I would break the clamp trying to remove the original driver. The second reason is that Sennheisers come with matching drivers, and replacing one would negate that. I could just replace both, but I couldn't be sure that both drivers would be matching. Maybe I'll just give Sennheiser a call tomorrow and see what solutions they give. Thank you for your responce.