Turns out that the battery was not charging. Also, the unit would not run from external power.
An examination of the PCB revealed that the outer leg of the 470uF capacitor in the SMPS was not soldered to the board. I suspect that the board was layout for a slightly different capacitor footprint as the one installed is not a good fit to the pads on the PCB.
Anyway, the GeoChron is now working again and I can log my up coming hike.