Nikon Coolpix 3100 Repair
The battery cover is held by a little hook of plastic, that with many changes of batteries can be broken. If the hook is broken, we can broke the whole door, because batteries push the door without the retention hook.
I’ve tried to repair the hook with paste, but the batteries really push hard. The best solution is to make two little holes and make a new hook with a thin wire of iron. I’ve made the holes with a pin and a hammer (with caution)