replacing NICd packs with std batteries

[Bernhard Haussler]

I "inherited" an HP 21 from a colleague who cannot resist collecting things that look like they could work. Being in Namibia the chances of laying my hands on a replacement battery pack and charger are slim. So I replaced the NICd cells with 2 std aa penlight batteries. The calculator works ! ! ! !

However, I am concerned that the higher voltage may cause damage. Can anybody give me advice?

Thanks
Bernhard

[DaveJ]

You should have few to no problems. many people have done it in the past. You can get individual NiCAd or NiMH rechargable cells also.

[Andrés C. Rodríguez (Argentina)]

In my experience, alkaline AA batteries are acceptable, the excess voltage is within tolerances. Of course, I cannot offer any warranty. Please never use the AC adapter with non-rechargeable batteries; only use it with proven, good rechargeables and with clean contacts. Failure to do so will damage your calculator in a split second and beyond repairability. If possible, just avoid the AC adapter, and use an external recharger.