Repair attempt of a broken NeoSPlan 5x
State of the objective
Back lens is moving freely and is completely dislodged from the lens.
A ruler slide appears as a blurry mess.
Lens groups
We can count 5 cells: 4 lens groups, 3 visibles on the next image (the top right one is a spacer). The first group is the front lens of the objective, still in the barrel.
In the order, left to right:
- 4th group (rear element) with the moving lens.
- 3rd group with the thick lens.
- 2nd group with the thick small lens.
- Spacer (on top) placed between the second and third groups.
Here with the spacer on top of the 2nd lens group.
Here the full stack assembled:
Fixing the cell
The lens appears to have some glue on the edges.
The idea is to press the lens and metal ring hot enough to melt the glue.
I’ll use my heatgun to gently heat the lens placed on top of the ring, and press it with a q-tip wrapped in lens paper.
Important: the lens is plano convex with the round side upward.
Reassembly
I marked all lenses just in case you are supposed to place them exactly at their original position.
Reassembling the lens groups was easy. I just placed the stack upside down on lens paper, and pressed lightly the body on it to bring them back in.
Result is surprisingly good. No obvious misalignment visible, even if it seems there is a slight ghost in the left direction.
I’ll have to try the pinhole method to measure any misalignment, but for now I will say it’s a success!