Pictures on this would help. It looks to me like the same type of end as on the aluminum keyboard. That being the case you may be able to the cap off and using a lot of pressure with a medium sized screwdriver, use the round barrel of the screwdriver burnish the opening where the cap goes back into round. Kind of like cutting an apple using one hand and stroking it out slowly. Here's the teardown on the keyboard to give you an idea of what the opening is like: [guide|5239]