[LargeFormat] Durst 138S focusing problem

[Don Wilkes]

Dear Clive, and anyone else with a 138S...

I'm having a problem with focus 'backlash', and can't seem to find a way to
adjust the beast.  If I overshoot very slightly while focusing (through a
grain scope), and then try to go back just a teensy bit, it overshoots the
mark terribly.  This has become pretty frustrating, as you may well imagine.

The manual is pretty mute on the subject, and I don't see anything in the
way of a tension adjustment (apart from the lock-down), so I'm a bit stuck.
 Any suggestions?  Lubrication, maybe? If so, with what -- silicone, lithium??

At first, I thought it was just because I was using the Beast to blow up
some 35mm work, and had the bellows pretty well jammed to its limits, but I
have the same problem when projecting 4x5.  Rats.

Cheers,
\dw