Well, in my case, the hole does not line up with the light pole. I removed and rotated the (filter?) insert. In the first series of photos, the opening in the casting measures 2.25" X 2.25" and the flange blocks the light pole. . On my other 23C2's this opening is 3" X 3" and the light pole is unblocked. I still think this may be a special housing (maybe for 6 x 6 production?).
Did you try turning and flipping the filter to see how it lines up with the light pole in all of the 4 possible positions?
Yes, I rotated it 360' One problem is the flange that creates the 2.25" square opening covers the light pole. I would really like to know what this set up is/was for. As I said, I have two "normal" 23C2's, but this one is a mystery to me.
Gerry
The idea is that you turn your enlarger into a safelight so you can put your paper in well. Personally, i took the red plexi out, and i use that drawer for filters on both my 23c2 and my 45mxt. Works great. I've never used the red filter, but i've heard bad things
That’s the older slide-in red “Safety filter” holder. Later Beseler simplified the casting and installed the much simpler (and much cheaper to make) sheet metal holder that swings into and out of position under the lens.
The change must have taken place during the production of the 23C II version because I have one with the slide-in filter, while the other two have the simpler pivoting filter holder.
The slide-in holder is mainly for the red filter. You’d use the filter slots above the condensers for VC or CP filters, or you could use a clamp-on holder for below-the-lens filters. However, the manual states that VC filters could be fitted to the slide-in holder if wanted.
See pages 5 and 11 of this PDF. On page 12 the use of VC filters in the above condenser slots is discussed.
Well, the mystery is solved. It seems that on the very early production 23C II XL's, the earlier production 23C lens housings (blue type) were used and just painted black by the factory. Thanks to all for your input.
Gerry