Hi I repair roll laminators for a living all around the pittsburgh PA area.
What model machine do you have? Do the exact opposite to increase. On most laminators turn the knob counter clockwise.
Both tensions should be set as light as possible and equal top and bottom, otherwise the film will curl which can lead to jams:( If you have futher questions feel free to call me telephone tech support is ALWAYS FREE:)
bob haller service and sales pittsburgh pa 412 366 4906, May 2013