A current issue with batteries for my HP-35 and HP-67 calculators

[aurelio]

(05-29-2020 03:00 AM)teenix Wrote:  

(05-28-2020 02:42 AM)johnhaley Wrote:  It’s been my experience that the 35 will function without the battery installed when used on the charger, but the 67 MUST have the battery installed even when using the charger

Thanks

Not sure if this is just experience or a question.

Page 312 of the HP67 user manual...

CAUTION
Operating the HP-67 from the ac line with the battery pack removed may result in damage to your calculator.

cheers

Tony

It's not reccomendecd but it is "quite safe to operate the basic calculator from the AC adapter/charger with the battery removed" if you do not need to use the card reader.
Michael de Estrada explained it well in this old thread.