Horizontal; Vertical - IBM 5100 Maintenance Information Manual

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DISPLAY REMOVAL AND RASTER
ADJUSTMENTS (Page 4 of 4)
Horizontal
The horizontal adjustment determines the overall width
of the 16 lines on the display screen. Use the width coil
on the display PC board for making this adjustment.
Before adjusting the width coil. be sure the display is
centered properly.
Vertical
The vertical adjustments (height. linearity. and frequency)
determine the overall height of the 16 lines of
characters. the height of the individual characters. and
the stability of the entire display screen. The vertical
adjustment potentiometers are located on the display PC
board.
1. If the linearity or height needs adjusting. and the
unit has a horizontal linearity sleeve. remove the
front cover for easier access to the potentiometers
(see 211).
2. Adjust the vertical frequency potentiometer for a
stable display.
3. Adjust the height potentiometer until the desired
overall height of the 16 lines is achieved. The
vertical frequency might have to be adjusted to
keep the display from rolling.
4.
Adjust the vertical linearity potentiometer until all
characters in the display appear to be the same
height. This adjustment and the height adjustment
are interactive and might require repeated
adjustments.
5.
Adjust the vertical frequency potentiometer until
the display begins to roll. then reverse the
adjustment until the rolling stops.
6. Recheck the height and the linearity.
7.
Replace the front cover if you removed it in step
1.
Width
Focus
Height
Video display unit with horizontal linearity sleeve
Horiz. Lin.
Brightness
Vertical Lin.
Video display unit without horizontal linearity sleeve
Display 241