How to replace the battery in a Matrix-1000 synth - detailed, step by step

Detailed (ie: boring) description of how to take apart an Oberheim Matrix-1000 synth, desolder the old buffer battery, and replace it with a new battery in a battery holder. The firmware is upgraded as well.
Tools used:
Crossblade screwdriver - all the screws are identical
Flat-blade screwdriver for removing the firmware EPROM
Plier and wirecutter
Tweezers
Desoldering suction pump, desoldering mesh
Soldering station or soldering iron suitable for electronics
Multimeter for testing
A computer/iPad with DIN MIDI to backup the memory banks
Materials used:
CR2032 battery
Plastic battery holder for PCB through-hole soldering, for 20mm pin grid
EPROM chip with Bob Grieb's V1.20 firmware
*Read the description here: www.untergeek....
*Get the V1.20 firmware upgrade here: www.untergeek....