I had this doorbell for a long time. It’s the battery one with the one screw at the bottom. I’ve changed batteries on it a lot.
But… We’ve been unable to remove the cover to change battery for several days. The right side of the cover is just stuck as if it was glued to frame!
Help!!!
Thanks 
Hi @user35162. In order to assist, we need to know which specific doorbell model you have. Thanks for this information.