Hmm, my above post isn't editable now so here is my summary.
The head of the unit is adjusted all the way up which is the labeled 35mm position, adjusting the height of that changes the cone of light on the film which changes the brightness of the image but in no way effects focus.
The El-Nikkor 50mm 2.8 lens does actually work now, I was using the lens board flipped over so the lens was in the shallow recess since I was trying to get it as high as possible to help solve my problem. This lens so barely fits under the sliding drawer in a 23c II (not the later type) that just the depth of the recess in the otherwise flat lens board is the difference between hitting it or not. So that problem is solved.
I had to take the panel off the back from the focus assembly area and crank the tension up on both the 4 set screws on the shaft the knobs mount on, which had started to work slightly loose, and more importantly the 4 screws for the 2 big tension straps. Otherwise as the bellows reached full compression the rollers were slipping and I wasn't getting the last critical bit of adjustment range I needed. This adjustment is in the manual. I also discovered that some irritating play that was making it hard to fine focus was between the knobs and the shaft itself, the flats inside the knobs aren't cut precisely enough so I will shim them with epoxy or metal repair compound to fix that.
(This paragraph edited after another test)
Now I can get the image in focus normally though when I crank the enlarger up to the top of its travel (over 22" which is a massive print that hangs off the base board) I use up every bit of focus adjustment, probably by design.
This means the lower bellows goes from fairly squished to smashed flat at full adjustment. The only way to change that would be to go to a different focal length lens since the distance between the film and lens has to be what it is to focus and that smashes the bellows, so no way to change that.
It does somewhat make sense since the 23c is technically a medium format (2x3 in the name) enlarger and so it makes sense for the smaller 35mm film size with 50mm lens to require operating right at one end of the adjustment spectrum. I tested a bad 80mm lens that came with the enlarger which would be about normal for medium format and it is in focus right in the middle of the focus adjustment range.
Maybe this will all be of use to someone in the future as I have seen this topic in several forums. I will start a new thread for additional questions later.
Last edited by PPPPPP42; 12-30-2013 at 12:25 PM. Click to view previous post history.