UpdateMay 25th: NOTICE: In the pictures of the wiring shown below the wires goes across the PCB both on the upper and lower edge. I later discovered that there was no room in the housing to allow wires to run over the lower edge, so I had to redo some of the wiring. This will be shown in the next update. I didn't update the pictures in this posting, partly as the Hackaday editor is VERY unstable when it comes to replacing/editing the pictures, partly because I think it is nice the logs correctly reflect the actual process ;)
Dismantling the KORE controller was pretty straight forward. Just notice that the red transparent round covers on the potentiometers and rotary encoder are actually threaded on the shafts. So these must be unscrewn to loosen the PCB from the plastic frame.
As there are 8 of the 360 degree eternal rotation potentiometers, each having two outputs, I needed an Arduino board with 16 analog inputs. And the ATmega2560 PRO with onboard CH340G USB to UART bridge is perfect. The ATmega2560 also have enough driving strength on the IO (typ 20mA sink current pr IO / 200mA pr port) to directly drive the onboard LEDs.
First you have to desolder all the ICs on the PCB. This can be done by applying generous amount of fresh solder over the pins on one side, and make sure to heat all the pins while carefully lifting that side of the IC up from the PCB using a pair of thins tweezers. Secondly do the same for the other side. This will leave a lot of solder residue on the PCB.
Finish off by removing all the residue solder with a solder wick.
NOTE: As mentioned in the update, this picture shows wires going across both top and bottom of the PCB, but due to space constraints, all wires need to go on top of the PCB. See pictures in later updates.