YOKE 1006769 - Caterpillar

The surface of the mirror used in the 1U5269 Mirror Tube may become scratched. The mirror tube is normally used with the larger 1U5268 Borescope. This combination provides a low cost way of looking out the side of the borescope. Since the mirror does not have a protective covering over it, the mirror's surface is exposed. If any carbon particles fall on the mirror's surface, extreme care must be taken to clean them off. The recommended way is to use a clean cotton swab and isopropyl alcohol. The use of a rag or shop towel is NOT recommended.
It is possible to extend the useful life of a scratched mirror tube. If the scratches are not very deep, place a small amount of extra fine automotive type polishing compound on the mirror's surface. Insert a wooden-handled cotton swab in the chuck of a Dremel® tool. Buff the surface of the mirror very lightly. If the scratches are deep and affect the viewed image, there are two options available. The 1U5269 Mirror Tube may be discarded and a new one purchased, or the mirror tube may be returned to the manufacturer for replacement at about one-half the cost of a new one.