Technical information
2.5.2.4.5 Video Levels and Cutoff Voltages
All adjustments must be made with the brightness control set at center
detent and the contrast control set at maximum. Select mode 4 (or mode 3
if not available) to display the test patterns.
1. Select option 3, pattern C (Full Screen Raster), and press the
spacebar to get a black screen.
a. Set RV014 (R.BKG) and RV034 (B.BKG) fully clockwise.
b. Adjust RV508 (G2) until a background raster is just visible.
c. Adjust RV014 (R.BKG) until raster has a red tinge, then readjust
until the red tinge just disappears.
d. Adjust RV034 (B.BKG) until raster has a blue tinge, then readjust
until the blue tinge just disappears.
e. Adjust RV508 until the background raster just disappears. When
the background color point is set correctly, the raster is white
or gray until it disappears. If it is not, repeat this step.
2. Connect a voltmeter between ground (GND) and ABL1 on connector D8.
PICTURE 44
Figure 8-13. Connector D8
3. Press the spacebar to get a full blue screen.
4. Adjust RV031 (B.DRIVE) to give:
(8517) -1.38 V dc.
(9517) -1.60 V dc.
5. Press the spacebar to get a full green screen.
6. Adjust RV021 (G.DRIVE) to give:
(8517) -2.30 V dc.
(9517) -2.15 V dc.
7. Press the spacebar to get a full red screen.
8. Adjust RV011 (R.DRIVE) to give:
(8517) -2.50 V dc.
(9517) -2.60 V dc.
9. Press PF3 to return to the setup patterns. Select option 2, pattern B
(50 mm square white block).
10. Press the spacebar to get a white block.
11. Adjust RV102 (SUB.CONT) to the highest voltage possible within the
range:
(8517) -0.45 V dc to -0.50 V dc.
(9517) -0.50 V dc to -0.55 V dc.
12. If the voltage is not within this range, repeat all the previous steps
for this procedure.
13. Press PF3 to return to the setup patterns. Select option 4, pattern D
(Gray Scale).
14. Check at maximum and minimum contrast that the blocks are evenly
gradated from black through to white with no color tinges. If they
are not, repeat this procedure.
15. Do focus and convergence adjustments after this procedure.
PS/2 Displays Maintenance Manual
Video Levels and Cutoff Voltages
¦ Copyright IBM Corp. 1993
2.5.2.4.5 - 1