Sometimes discharged battery's electrolyte oxidaze internal pads for batteries.
This may not be visible to the naked eye ...
This oxidation (the electrolyte), can also cause a short circuit between the pads and overload batteries.
Solution: Attention that the camera is upside down (with battery hole bottom), and with a wooden stick, cotton and alcohol clean both the pads and insulation between.If needed you can use small screwdriver for cleaning.Let the alcohol to evapurate well, and after a while do test.Maybe this help ..
