Jamming Fs-527 with pk-517 j72-43

Hi,

I'm having trouble with paperjams in the punch unit.
the paper stops in the punch unit for an unknown reason.
i checked all the connectors and switched the sensors
i oiled the punch unit, checked the settings in service mode ( pk517 - 2 holes)

i really have no idea why the paper just stops during operation.


any ideas?

greets