Polar 76 em problems

Hello
I remove the fake plate and replace it, but it still doesn't go beyond 7cm.
There is nothing in the slot where I marked, it is empty, I think the button is missing, where can I find it?

 

Remove the front cover to find switch and bracket on the frame above electrical box
Or find the plug on rear panel and follow cable
Might have come loose and dropped down.

 

thank you