Hi risk process this. I carefully levered at the top edge then used a very long bladed craft knife (the type with the snap off blades) to cut across the glue. My main chip didn’t actually seem to be stuck
Adjusted the click, put back together. Pressed power button. Nothing. Then the thing starts getting super hot so i pop the batteries out and take the back off again. Can’t see anything damaged or in the wrong place but something above the main chip got hot enough to melt the plastic of the back.
No harm in trying once more. (maybe). now it seems to work. very odd.