Easy fix, but mind your screws

Mein Problem

Weak battery.

Meine Reparatur

Easy fix, would have replaced sooner had I known.

Mein Rat

Mind your screws. They are very small. I found supplementing screwdrivers with a rare earth magnet to be helpful—not only because it prevented loss of screw but also aided in retaining proper orientation of screw. I used a blowdryer on low setting to coax battery out.