oko lavamat 605 program selector ON/OFF switch problem?

The 11-setting programme selector switch with programme cycle indicator has a fault with the ON/OFF push/pull switch. The programmes work and run OK and the machine stops at the end the selected programme. PROBLEM the machine cannot be turned OFF by pushing the knob in. The in/out movement of the switch is too loose now - when working properly it used to 'snap' in or out when used. How do I get at the switch to examine it? Help anybody.
Model AEG OKO Lavamat Electronic 605 636 406 000