Recharging the NiCad battery of a standard full-size Welch Allyn otoscope handle (Model 71000-A) requires accessing the portion of the handle that plugs into a standard wall outlet. To do so, unscrew the otoscope handle at midpoint to reveal the hidden prongs. While this sounds relatively straightforward, a subtle handle design idiosyncrasy occasionally causes some confusion. If the handle is 
not unscrewed at the precise mid-point junction, rather than gainingaccess to the prongs, unscrewing the handle at midpoint will reveal the upper portion of the rechargeable battery compartment. The key is totake note of the black ring located approximately at mid-point of the handle (refer to image of otoscope handle). As illustrated in
Above black ring
Below black ring
the images to the left, unscrewing the handle above the black ring will expose the prongs needed to recharge the battery whereas unscrewing the handle below the black ring will expose the top portion of the battery compartment.
