i recently bought a new Holga!
the 120 pan model, you can see Peter R's write up on it here >
http://www.filmwasters.com/forum/index.php?topic=5074.0the plan was to modify the holga before use.
there are a few design faults which i have experienced with my other holga 120.
first up was to remove the foam roll tensioners that were stuck inside the roll chambers as these eventually get ripped off the
inside wall and wrapped in with the exposed film causing a "fat" roll and major light leaks when removing the exposed roll.
the replacement tensioner is a simple spring or zig-zag spacer to sit under the feeding roll and in the U shaped groove on the
bottom of the chamber so it cannot come loose after the camera back is fitted. depending on the thickness of the plastic used
a simple double fold or 3 or 4 folds can be made for the spacer. here i used the top of a deoderant can as it is curved so it will
create slightly more resistance under the roll.
a similar spacer can be made for the take up roll so both rolls are at the same height. the aim here is to create just enough
tension to keep the film flat across the the frame window to get an even exposure etc. it is easy to create too much tension
making the advancing of each frame quite difficult and increasing the chances of damaging the film.