Horizontal Dc Raster Centering; Horizontal Phase; Horizontal Size; Vertical Hold - Zenith ZCM-1490 Service Manual

Horizontal DC Raster Centering
The horizontal DC raster centering control (R3001)
sets the left-to-right centering of the raster within the
bezel opening. To adjust the horizontal DC raster
centering: .
1. Tum the G2 control until the raster just appears.
2. Adjust R3001 to center the raster horizontally
within the bezel opening.
3. Tum the G2 control until the raster just disap-
pears.
Horizontal Phase
The horizontal phase control (R3420) sets the lett-
to-right position of the display within the raster area.
To adjust the horizontal phase:
.
.
1. Use the fill screen test to fill the display area
with text.
2. Center the external horizontal centering control
(R3418) located on the rear panel. .
3. Adjust R3420 to center the display from left to
right within the raster area.
Horizontal Size
The horizontal size controls (R3402 and R7106) set
the amount of horizontal (Ieft-to-right) raster deflec-
tion. To adjust the horizontal size:
1. Use the fill screen test to fill the display area
with text.
2. Center the external horizontal size control
(R3402) located on the rear panel.
3. Adjust R7106 (located on the PIN board) ·for a
display width of approximately 256 mm
±
2 mm
(10.07 inches).
Page
4·6
Vertical Hold
The vertical hold control (R2117) prevents the display
from rolling upwards or downwards. To adjust the
vertical hold:
1. Adjust R2117 to stabilize the display by turning it
first to one extreme and then backing off until
the display just stabilizes. Repeat this procedure
from the opposite extreme until the display just
stabilizes. Set R2117 midway between the two
settings that stabilize the display.
2. Verify that the display is stable in all three video
modes by using software that forces the monitor
to operate in each of the three modes.
Vertical DC Raster Centering
The vertical DC raster centering control (R2148) sets
the top-to-bottom centering of the raster within the
bezel opening. To adjust the vertical DC raster
centering:
1. Use appropriate software to fill the screen in the
480-line mode.
2. Adjust R2148 to center the displayed video verti-
cally within the bezel opening. R2148 should be
set within the middle portion of its range when
this adjustment is completed.
Vertical Size
The vertical size controls (R2124, R2169, and
R2158) set the amount of vertical (top-to-bottom)
raster deflection.
So
that the vertical size remains
constant in all three video modes, there are three
sub-size adjustments that must be set. To adjust the
vertical size, center the external vertical size control
and then proceed to the sub-size adjustments for
each mode. .
Adjustmerts