Technical information

2.6.2.3.5 Video Levels and Cutoff Voltages
Proceed as follows.
Note: The use of a color analyzer is recommended for steps 1e, 4, and 6.
1. Select pattern C, and press the keyboard spacebar until the black
field is selected.
a. Set RTH110, RTH210, and RTH310 (Cutoff Potentiometers) fully
clockwise, as viewed from the video card shield.
b. Set RTH101 and RTH301 (Gain Potentiometers) fully 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 screen 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 screen is just not
illuminated.
2. Select Pattern B, and press the keyboard spacebar until the white
block is selected.
3. Ensure that the Contrast control is at midpoint.
4. Adjust RTH101 (green) and RTH301 (red) for correct white color points.
5. Set Contrast to midpoint.
6. Set RT17 (Maximum Contrast) to midpoint.
7. From the main menu, select Display Mode 1.
a. Select pattern D, Gray Scale Blocks.
b. Adjust RT18 (G2 Fine Adjustment) to midpoint.
c. Adjust G2 on the EHT so that the top right-hand block is visible,
and the block to the left is just visible.
8. Return to the main menu, and select Mode 4. (If Mode 4 is not
present, go to step 9.) Select Pattern D, Gray Scale Blocks, and
adjust RT16 for the same condition as that described in step 7. The
block pattern should now look the same in all modes.
9. Return to Pattern D, Gray Scale Blocks. 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
¦ Copyright IBM Corp. 1993
2.6.2.3.5 - 1