Easy fix, but mind your screws

Mon problème

Weak battery.

Ma solution

Easy fix, would have replaced sooner had I known.

Mon conseil

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.