How to fix uneven lighting from a Lamplighter box
Sometimes you will find that not all of the fibers inserted into a Lamplighter box provide an even light.
Most of the time this is due to only a few fibers being inserted into the box and one of them curling a bit more than the others. The fibers naturally curl as this is how they come off the mile long spool they are stored on. This curling can cause some of the ones inserted into the Lamplighter to not receive as much light as others that may lie a bit more parallel to the axis of the hole int the box. Here are some easy solutions to this problem which I have used to fix this problem on my own layout.
1. Add some short fiber lengths (say 4" long) to better fill the tube that is inside the Lamplighter box, or
2. insert some plastic stirring straws, the sort you get from a coffee shop, or
3. Whatever you have that will fill the space without scratching up the insides, or
4. Straighten the fibers as described in blog post - "How to Straighten a piece of Fiber Optic Cable:
After you do the above, look for the fiber / light that is dimmer, remove the fiber from the Lamplighter box then add it back in at the center of the bundle and see if that improves the lighting.