Advanced Operation
25
Section 6:
Advanced Operation
The procedures in this section allow a user to optimize or troubleshoot the VIP 4500. Given the
advanced nature of the procedures listed, it is recommended that users perform them under the
supervision of Daktronics service personnel.
6.1 Adjusting Screen Color Balance
For proper color display, using a color pattern generator is essential. The connection allows
for SMPTE bars to display on a Daktronics LED video display.
SMPTE bars are multi-purpose test patterns used as an adjustment reference to verify the
correct operation of a video display. Refer to
With the Calibar
TM
attached so the bars display on the Daktronics LED video display, perform
the following steps:
1.
Adjust the contrast so the white reference square
in the lower-left corner looks bright and clean.
The white should not spread or bleed into the
darker squares surrounding it.
2.
Adjust the display brightness so the three small
gray and black rectangles near the bottom-right of
the pattern are clearly visible; this area is called
the PLUGE. Reduce the brightness just until the
line separating the first and second
rectangles disappears.
3.
If a vectorscope or waveform monitor is present, use the SMPTE bars to check system
gain by feeding the pattern to the Daktronics LED video display and to the monitor with
the scope.
The video line feeding the WFM must end in one 75-ohm termination. Color bars appear on a
WFM as six vertical, shaded rectangles called chips. The white reference square of the pattern
shows up on a WFM as a line at the top of the yellow and cyan chips. Using the vertical
position on the WFM, center the blanking level at 0 IRE. Adjust the video device’s gain to
place the line of white reference square at 100 IRE. When the low-pass filter is selected on a
WFM, IRE levels should be as follows:
•
Gray 77
•
Green 48
•
Yellow 69
•
Magenta 36
•
White 100
•
Red 28
•
Blue 56
•
Blue 15
Figure 17: SMPTE Test Bar Display