Above the enlarger lens dust and scratches question

[chassis]

Update. I got brave enough to pry off the retaining ring holding the upper condenser in place. Here is the disassembly sequence for a Beseler 45V-XL condenser lamp house. I don't know if there are variations with other Beseler 4x5 condensor lamp houses which would prevent these steps from working on earlier versions.

1. Loosen one black knob and remove bulb assembly.
2. Loosen three black knobs and remove cone assembly.
3. Remove filter drawer.
4. Slide two retaining clamps on the right and left sides of the condenser housing so they are applying no pressure on the housing
5. Lift the condenser housing up and away. Place on a flat surface with a towel under the housing.
6. Remove three screws, shims and spring nuts.
7. Remove flat cover glass.
8. Carefully using a medium length, small flat screwdriver, pry the wire retaining ring away from the barrel of the housing, and up.
9. Remove retaining ring.
10. Remove upper condenser lens.
11. Remove one screw holding spacer sleeve.
12. Slide spacer sleeve up and out by grasping one edge and pushing it so as to make the diameter of the sleeve smaller so it comes out easily.
13. Remove lower condenser lens.

I cleaned inside the condenser housing after everything was taken apart. The lenses were cleaned with windex and paper towels. Assembly is the reverse of disassembly. Pictures would have helped, but I didn't take them. Apologies.

Hopefully this helps with dust.

[Mark MacKenzie]

This may not be related but on my D2 condensors there is a deep scratch about an inch long. If I print at f32, it will show in the print. So...... I print at f8 or so. I've had to use a voltage regulator so my exposures aren't absurdly short. I think it is sharper just a bit at f8 also. Maybe diffraction at f32. I just got a cold light so it should no longer be a problem.

Old condensors are not like a coated lens. They will get dusty and accumulate grime. They need attention. My old Omega would shed black specs of the paint inside.
Best luck,
Mark

[chassis]

Mark, good point about the aperture imaging defects. I want to use a larger aperture, which should also help reduce non-negative-plane defects. I need to change to a lower wattage enlarger bulb to maintain the desired 10-20 print exposure times.