electronics problem

Hello,

>our elderly Cafamosa CF 220, which I have been maintaining, waiting for and keeping running for years with great effort, is no longer functional. It started with spontaneous shutdowns and at some point she wouldn't turn it on again.
In the past it was mostly the heat sensors on the thermoblock and after their exchange the machines worked again (we now have 3, a spare part donor, the "holiday machine" and those for daily use).
I have measured everything I can measure: All switches OK (incl. pomace container and lid closed), the lines also, the main board I have already exchanged, the on/off switch also, in each case without result.
When I press the on/off button, a short click of the button will not cause anything to happen.
Thanks to a plug error at the pomace container switch on my part, I came across a phenomenon.
I had reversed the switching phases so that the machine, with the marc container inserted, was led to believe that the marc container was outside. And lo and behold, she at least let herself be switched on/off again and also indicated that the grape marc container was missing.
switch-on relay is basically OK.
As soon as the marc container was removed, however, it went out again. After I had fixed the plug error, then of course the other way around. Container outside, machine goes on and shows "missing marc container ", inside, machine goes off.
Actually I know the other way around. If you try to start the machine with the pomace container removed, it stops, but starts normally with the container inserted.
This is all illogical. It seems as if this switching signal is "misdirected" from the pomace container and suddenly unfolds a different mode of action.
Has the error ever occurred to anyone? How can it be repaired?
I know mechanics and analog electrics quite well, but I have no plan of electronics.

Thanks for info.

Greeting Thomas