hi
the boot button should spring out when pressed
first press, should open the top half, second press , the bottom half
on mine the surround was ropey looking so i took it all to pieces only to find that you cannot get into the contacts, all you can do is spray and spray and spray with wd 40 i got it working and has been now for about 4 years since
but it is dead easy to change (when you have the boot open)