Dear Forum,
One of my sons, knowing of my interest in old HP calcs, gave back to me for Christmas the 31E that I had given him in 1981.
It is in excellent condition with Owners Manual, AC adaptor, but minus the battery pak. My son says it works fine with just the adaptor. But I remember reading in the Forum as to the 25C, never to use the calc on the adaptor without the pak in place.
Questions: Is this true for the 31E and can I somehow rig up a pak using two AA rechargable batteries?
tm