Neither foam seals nor pressure plate.
Thanks Mark. I'm unsure what to test for if the lens is faulty.
I have replaced all foam seals surrounding the door at least 6 months ago. They are as good as new.
I inspected the pressure plate and it appears to be working OK. Its springs compress about 1.5mm when closing the lid. There appears to be even pressure along the two outer rails. Placing ink on pressure plate and closing lid transfers ink to a piece of paper which wasn't quite wide enough so I moved it across and closed lid a 2nd time.
IMAG0399_inside my Mamiya C330. outer rails higher than inner 120 film rails.jpg
IMAG0397_pressure plate deposits ink onto outer rails.jpg