HP12C battery problem solved and studying RPL

[DaveBr]

Quite a while ago, I found a HP12C on top of a garbage can with a sticky note on it that indicated it was broken. I put the 12C in my pocket and when I got home, I tossed it in a drawer, intending to see if I could get into work as a spare in case my wife's 20+ yr old 12C croaked.
Fast forward 5 years or so to this morning. I was looking for something in a drawer and found the salvaged HP12C (the sticky note was still on it). I pressed the ON button and the calculator showed 0.00 in the display. A couple of key presses later, I thought all was well. When I set the calculator down on the counter, the display faded out and the calculator wouldn't turn on - until I picked it up. It worked fine in my hand. Time for disassembly.
When I opened the calculator (easy), I found the 3032 battery holder contacts were bent, making compression contact and there was a lump of plastic under the battery. The plastic lump was one of the many heat-staked posts holding the internals together that had broken off and gotten under the battery.
I was really disappointed at the design of the battery holder. I've seen better in $5 children toys. My wife's older 12C uses three 357 batteries and is rock solid. This newer one - not so much.
BTW- The newer 12C now works fine.
Dave