My Jura A1 espresso machine’s start button is bugging

When I want to start the machine, I need to push at least 20 times the start button. Each time I click the display turns on, but the start-up process is not ignited. On the contrary when I click to shut down the machine the button reacts immediately.

I already changed the start-up button, but that did not work out. It seems to be an electrical problem on the circuit board. Anyone encountered the same problem? Can I replace the mother board of the machine? Where could I buy this?