SPIESS Heinz: I noted that 40-some years ago I had added some additional functions by hand on the keyboard (F, MX, EX,1/x,X^2,+/-). That reminded me that this must have been my first (but certainly not the last!) experience for ‘modding’ an electronic device: making available functionality that was built in the device, but hidden from the user. So, I opened it again to see what I actually had modified then to access the additional functions: It was the solder jumpers on the keyboard PCB which I changed from upper to lower contacts. From what I know now after searching the WEB, this had changed my ELKA: 103 into an ELKA: 130