I ordered a second hand illuminator carrier off ebay – it was cheap but I did not realize it was broken!
However, I think I have successfully fixed it.
Damaged carrier as it arrived from ebay – these photos show that the plastic gear strip is cracked. On the other side of the illuminator it has also had its teeth stripped:
The following two photos show that the illuminator can hard move – these show the two extremes – it turned out this was due to stripped teeth and bits of plastic caught up in metal teeth on roller on illuminator carriage.
Next photo shows stripped teeth:
The following picture shows a similar but fully working item on my microscope. Note that the illuminator carriage sits close to the top.
I removed the plastic strip:
I used water proof PVC glue:
I stuck the plastic gear strip back down – BUT other way around from way it came out so that the illuminator carrier sits away from the stripped area when in use: