Hughes JVC 200, Service Manual

Page: 129 / 140

Chapter 5---Troubleshooting
PROBLEM CHECK POSSIBLE SOLUTION SECTION
XY Convergence
Not enough range in Red
or Blue XY convergence. Adjust Red or Blue
CENTERING to match
Green.
5.5.11
Picture Color
Balance
Red, Green, or Blue is
missing in the image.
ILA
®
assembly bias
voltage is incorrect or
there is no signal-replace
Video Amplifier Board.
4.13
Red, Green, or Blue
lacks color.
Replace ILA
®
assembly
or Video Amplifier Board.
4.16, 4.13
Grey scale test pattern is
correct but image color is
incorrect. Readjust Contrast. User’s Guide 5.11.2
Black image is
overdriven. Adjust Threshold, Black
level, and Brightness. User’s Guide 5.10.2,
5.9.1, 5.11.1.
Bright Red, Green, or
Blue area on screen
limited to corners or
edge.
Adjust ILA
®
bias and
shading.
User’s Guide 5.7, 5.10
Grey scale is Green in
bright areas. Subtract Green
Sensitivity Offset and add
Red and Blue. User’s Guide 5.9.2
Grey scale is Red in
bright areas. Subtract Red Sensitivity
Offset and add Green
and Blue. User’s Guide 5.9.2
Grey scale is Blue in
bright areas. Subtract Blue Sensitivity
Offset and add Green
and Red. User’s Guide 5.9.2
Picture-Various
Problems Out of focus, blurry area
on image limited to Red,
Green, or Blue. Clean oily spot off CRT,
Prism, or Projection
Lens. 3.12
Small, dark line or dot in
Red, Green, or Blue
image. Scratch in optics or CRT
burn. Replace CRT. 4.15.
Bubbles in Red, Green,
or Blue image.
Replace affected ILA
®
assembly.
4.16.
Image ghost in picture. Replace burn-in CRT or
ILA
®
assembly
4.15, 4.16
Reversed ghost image on
screen. If projecting through
glass, prevent light from
reflecting back into the
lens.
Picture lacks depth of
field. Adjust Contrast or
Brightness.
User’s Guide 5.11.2,
5.11.1
5-8 Model 200 Service Manual