HP 30b Mode Settings

[BartDB]

With all HP ARM based calculators, my first suspicion is the battery.

Please use a good brand from a reputable supplier. Cheap ones from e.g. eBay will not do.

Coupling the ARM processor design with coin cells was not a good decision. These ARM based calculators use current in high pulses which coin cells are not designed for (they have a high internal resistance compared to e.g. AAA cells). The battery low warning is not reliable on these calculators either.