Usage:
Reference: Operating Manual, Form NEHS0504, "Using The Inspection Borescopes " for 1U5268 and 8T9290 Borescopes.
Description of Change: In March 1989, Caterpillar's supplier of the 8T9290 Borescope provided an improved version of the borescope. A new light bulb with an improved design is used. The new design provides greater protection to the light bulb, and produces a larger field of view. These changes will increase the service life of the light bulb. Since the physical mounting of the new light bulb is different, a new part number for the light bulb is required.
Adaptable To:
The new 4C6493 Light Bulb (B) is used in the improved 8T9290 Borescope. The former 1U6862 Light Bulb (A) is used in the earlier version of the 8T9290 Borescope. If the light bulb can not be removed from the cap of the borescope, replace it with the former light bulb (A) instead of the new light bulb. Complete instructions for the correct operation and maintenance of the borescope are included with each unit. Additional copies of the Reference are available through normal literature ordering channels.
NOTE: The new light bulb will only work in the improved 8T9290 Borescope. The former light bulb (A) CAN NOT be removed from the end cap.
(A) Former 1U6862 Light Bulb. Notice that the light bulb is exposed and has a metal tab on the side. (B) New 4C6493 Light Bulb.