Replacing the Garmin GPS 12CX's memory battery

Finally getting this rare and unique GPS working perfectly. Should also serve as a nice guide to replacing the memory battery in any older Garmin GPS, especially the GPS 12 series. Usenet post I made regarding the battery voltage glitch: https://groups.google.com/forum/#!topic/alt.satellite.gps/eGMVLojmAb0 Original video of this GPS: https://www.youtube.com/watch?v=fqefiCPUD6c