Classic (HP-67) charger / battery problem

[Johnboy]

Hi All,

I am trying out a few battery packs, all rebuilt, but with varying ages of rebuild. Some are NiCd and some are NiMh. They all seem to charge to around 3.6V ok, and when charging, the calculator turns on and works fine.

If I remove the charger, the calculator doesn't come on. I have check the continuity between the two outer charge socket pins, and it's all good. When I measure the voltage between the charge socket middle pin and outer pins, it's only 3.0V with the calculator turned off, and less that 1.0v when I turn it on.

I get similar measurements for all (5) battery packs. Does this indicate the battery packs are all bad despite charging to 3.6 (even 3.8 for one) ?

Any suggestions welcome.

Thanks
John