It's 5 screws, be careful when taking the back cover off as it normally pops the triggers off, it's a battery you can unplug and just put a new one in. When you do take it apart, clean the contacts by the triggers too, as they get dirty and sometimes stop registering. I've taken apart my Dual shock a few times. I had an issue where the left analogue was "stuck" so the character just walked in circles, spongy triggers (there is a little metal piece that looks like a paper clip) replaced one of those and it works.