5-1 ZEROING OPERATIONAL DEFECTS
Operational defects relate to the reliability of the image intensi- fier and are an indication of instability. If identified, they are an immediate cause for rejecting the ATN NVM-14. They include shading, edge glow, flashing, flickering, and intermittent opera- tion.
a. Shading
If shading is persistent, you will not see a fully circular image (Figure 5-1). Shading is very dark and you cannot see an image through it. Shading always begins on the edge and migrates inward eventually across the entire image area. Shading is a high contrast area with a distinct line of demarcation. Return the ATN NVM-14 to the maintainer.
Figure 5-1
Shading
NOTE
Make sure the shading is not the result of improper eye-relief adjustment.
