Compaq Portable 286 Compaq Portable Computer, Compaq Plus Personal Computer, a - Page 129

Removal and Replacement Procedures., the display is equal.

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display unit. 14. Use the CTRL + ALT + < command to place the display in the low resolution graphics mode. Press and hold down the CTRL and the ALT key and press the less than ( command to place the display in the high resolution mode. Press and hold down the CTRL key and the ALT key. Press the greater than (>) key. Then release all three keys. Using the adjustment tool, adjust the HI SCAN HT control pot so that all characters appear at the desired height. 16. If characters on your display appear taller or shorter near the top of the display than those near the bottom, a vertical linearity adjustment is necessary. Using the VDU adjustment diagnostic, see Chapter 4, "DIAGNOSTIC Procedures," for more information on the VDU adjustment program. 17. Using a plastic adjustment tool, turn the VERTICAL LIN control pot until all characters appear equal in height. NOTE: 1. This adjustment may affect the character height enough to warrant a readjustment for character height. 2. If the vertical linearity control does not exist on your video display unit, it is preset and controlled by the video display unit. 3. Steps 13 and 14 should be repeated after each adjustment until the display is equal. 18. If your display is shifted to the right or left, a horizontal display centering adjustment is necessary. Two pots control the centering of the display. One is the MASTER VID CTR pot, which shifts the display in both a high and low resolution mode. The other one is the HI SCAN CTR pot, which affects the display in high resolution mode. NOTE: Do not use excessive force when making adjustments on the video display unit. 19. Use the CTRL + ALT + < command to place the display in the low resolution graphics mode. Using the adjustment tool, adjust the MASTER VID CTR pot so that the display is in the center of the screen. 20. Use the CTRL + ALT + > command to place the display in the high resolution mode. Using the adjustment tool, adjust the HI SCAN CTR pot so that the display is in the center of the screen. If your display experiences a problem other than those covered in the previous 20 steps, replace the video display unit. For video display unit removal and replacement procedures, see Chapter 7, "Removal and Replacement Procedures."

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display unit.
14. Use the CTRL + ALT + < command to place the display in the low resolution
graphics mode. Press and hold down the CTRL and the ALT key and press
the less than (<)key. Then release all three keys. Using the adjustment
tool, adjust the MASTER HT control pot so that all characters appear at
the desired height.
NOTE: Do not use excessive force when making adjustments on the video
display unit.
15. Use the CTRL + ALT + > command to place the display in the high
resolution mode. Press and hold down the CTRL key and the ALT key.
Press the greater than (>) key. Then release all three keys. Using
the adjustment tool, adjust the HI SCAN HT control pot so that all
characters appear at the desired height.
16. If characters on your display appear taller or shorter near the top of
the display than those near the bottom, a vertical linearity adjustment
is necessary. Using the VDU adjustment diagnostic, see Chapter 4,
"DIAGNOSTIC Procedures," for more information on the VDU adjustment
program.
17. Using a plastic adjustment tool, turn the VERTICAL LIN control pot until
all characters appear equal in height.
NOTE: 1. This adjustment may affect the character height enough to
warrant a readjustment for character height.
2. If the vertical linearity control does not exist on your video
display unit, it is preset and controlled by the video display
unit.
3. Steps 13 and 14 should be repeated after each adjustment until
the display is equal.
18. If your display is shifted to the right or left, a horizontal display
centering adjustment is necessary. Two pots control the centering of the
display. One is the MASTER VID CTR pot, which shifts the display in both
a high and low resolution mode. The other one is the HI SCAN CTR pot,
which affects the display in high resolution mode.
NOTE: Do not use excessive force when making adjustments on the video
display unit.
19. Use the CTRL + ALT + < command to place the display in the low resolution
graphics mode. Using the adjustment tool, adjust the MASTER VID CTR pot
so that the display is in the center of the screen.
20. Use the CTRL + ALT + > command to place the display in the high
resolution mode. Using the adjustment tool, adjust the HI SCAN CTR pot
so that the display is in the center of the screen.
If your display experiences a problem other than those covered in the previous
20 steps, replace the video display unit.
For video display unit removal and replacement procedures, see Chapter 7,
"Removal and Replacement Procedures."