I just acquired a Beseler Pringmaker35 in TLC-required condition. What I cannot figure out is how to adjust the annoying backlash in focusing knobs. There's enough of it to blow an image out of focus. Here's what happens... Put a film in and I raise the bellows slowly lower the bellows by turning the knob to focus At this point, the image is in sharp focus If I touch the knob at this point, it turns slightly without much resistance, perhaps a degree or two. With it, the lens moves about 1mm or two. Just enough to mess up the focus. Put in other ways, the knob moves the lens as designed but there is a very small (one or two mm worth) turn that has very little resistance, and beyond it, there is a good resistance. The knob turns very lightly for this mm or two. This is enough to mess up my focus. Is this the nature of this enlarger or is there an adjustment available?