614 Appendix B Image Reference
Description The primary version has a single white box in the center of active video. The box size is
controlled by the MSIZ system parameter. The secondary version adds four boxes in the
corners of active video.
Test Brightness control adjustment
Purpose The wrong brightness setting may cause other tests such as Contrast, Focus, and Beam
Size to be invalid. An accurate brightness setting helps give repeatable measurements
throughout other tests.
Method Center your light meter probe within the center square and adjust the monitor’s brightness
control to obtain the required light meter reading.
Test Brightness uniformity
Purpose The light output of most picture tubes varies slightly when measured across the CRT face.
This test can be used to verify that the light output variation is within your specification
limits.
Method Select the inverted version and perform the Brightness Control Adjustment test on the
center box. Then, center the light meter probe in each of the corner squares and note the
reading you get for each square. The deviation between each of the corner readings and
the center reading should be within your specification limits.