Durst 601 focus knob reassembly; HELP

[Richard Jepsen]

I just purchased a 601 CLS in excellent condition. The focus control assembly fell out while trying to eliminate minor binding. The screw and bracket need to be reassembled. The knob remains in the head. I need help, directions, on how to reassemble in order to focus the bellows.

 

[Richard Jepsen]

Clarification; the rectangle flat bracket, see picture on previous post, fell out when I tightened the set screw. Currently the focus knob rotates in the head housing without activating the bellows. I assume this bracket holds the knob so a cam located on the knob shaft can activate the bellows extension. Any help would be appreciated.

 

[Arvee]

Richard:

I checked on my 601 and it appears that the black rectangle is a tensioning device. The screw threads into the chassis and adjusts the amount of tension that the rectangle applies to the two wheels on the knob assy. If you look up inside, there is a slot that the rectangle goes into. Hold the rectangle in position and then start the screw with the head of the screw holding the rectangle in place while tightening the screw will increase the pressure on the wheels/rollers.
HTH,

Edit: forgot to add that the screw passes through the u-shaped cutout in the rectangle.

 

[Richard Jepsen]

I got it installed. Fred, as you described, the bracket fits in a slot with the u shaped notch on top. The screw fits through the notch and is screwed into the tap hole.

The enlarger had been been stored. The bellows were not moving freely. Working white lithium grease on the rails fixed the resistance.

This was a forward design for the late 60s. I don't know of another modular design at that time. For a compact enlarger its heavy due to metal castings, a huge bearing to attach the head to the column, and a robust elevation column.