Pfaff 145 H4 alternating presser foot not touching needle plate

[Woodpecker]

The outside presser foot on my Pfaff 145 H4 doesn’t fully contact the needle plate. I can slide a playing card underneath it when the presser foot lift lever is down. This occurs even with the presser foot tension on the maximum settings. I’m beginning to suspect that maybe the knee lift is not fully releasing. Is there another adjustment somewhere that I may be missing? 

Edited June 20 by Woodpecker

[Michiel]

You can adjust the height of the presserfoot

look into the manual or search on the internet

Should be one or two screws on the back of the machine, you find them also if you follow the presserfoot bar into the head of the machine