Technical information

2.7.2.3.5 Video Levels and Cutoff Voltages

Proceed as follows.

Note: The use of a color analyzer is recommended for steps 2e, 5, and 7;

see Procedure Using a Color Analyzer on the next page.

1. Select option 3 for Mode 3 timings.

2. Select pattern C, and depress the keyboard spacebar until black field

is selected.

a. Set RV631, RV651, and RV671 (Cutoff Potentiometers) fully

counter-clockwise, as viewed from the video card shield.

b. Set RV600, RV632 and RV652 (Gain Potentiometers) fully

counter-clockwise, as viewed from the top of the video card.

c. Set the Brightness control to center detent (midpoint), and the

Contrast control to midpoint.

d. Adjust G2 so that the background raster is just not illuminated.

Set the Brightness control to maximum.

e. Adjust the cutoff potentiometers for a correct white color point.

f. Set the Brightness control to center detent (midpoint). If

necessary, adjust G2 to ensure that the background raster is just

not illuminated.

3. Select pattern B, and depress the keyboard spacebar until white box is

selected.

4. Ensure that the Contrast control is at midpoint.

5. Adjust RV652 (green) and RV632 (red) for correct white color points.

6. Set Contrast to maximum.

7. Set RV600 to midpoint.

8. Select pattern D, Gray Scale Blocks.

9. Check, at maximum and minimum contrast, that the gradation of the

blocks is even from black through white with no color tinges.

10. Check that there is no color smearing.

If steps 9 and 10 are not satisfactory, repeat this complete procedure.

PS/2 Displays Maintenance Manual

Video Levels and Cutoff Voltages

2.7.2.3.5 - 1