My original HP-25, ailing

[Peter Klein]

I decided to get the Panamatik ACT repair kit. I thought about the more expensive LP (Low Power) version that replaces everything but the keyboard, case and LEDs. But since I have a Voyager and several Pioneers with most of the LP features I'd use, I decided that I'd prefer the standard ACT. It retains the 25's original character, adding a few welcome features including "constant memory."

I also figured out an intermittent battery issue that has been plaguing me from the start. The following description assumes you are looking at the calculator and battery holder upside down, as they would be when you remove or insert the battery. Years ago, I removed the cover of the original battery holder with a razor blade so I could put my own rechargeable AAs in. I then tape it shut with scotch tape.

There was just enough space or play in the above arrangement that when the battery contact pushed the positive "cap" of the right hand battery (+ side) back against the spring tension, it could slide up. A bit of the cap would stay caught behind the hooked tabs that go into the slots above the calculator battery contacts. These contacts normally touch the battery near the bottom of the positive cap, not the center. With the cap shifted up and back, there was intermittent contact to no contact at all.

The fix was to make an approximately 1mm thick shim out of the end of a plastic garbage bag fastener. I taped said shim to the inside of the lid of the battery case, in the curved area just behind the battery's positive terminal. Problem solved.