Service manual

IMl035
Section 5
ADJUSTMENT AND MAINTENANCE
5.1 HORIZONTAL ADJUSTMENTS
With a crosshatch signal applied, adjust video centering control, Al03 to center
the video within the raster horizontally. Adjust Ll02 for best horizontal lin-
earity. Do not adjust Ll02 core out farther than necessary as this causes ex-
cessive power to be consumed.
Adjust Ll03 for desired width.
5.2 VERTICAL ADJUSTMENTS
With the crosshatch signal applied, adjust vertical hold control AlOl to lock in
the picture.
Adjust vertical linearity control Al02 for best overall linearity. This control
affects the vertical frequency slightly and might require a readjustment of the
hold control. Adjust vertical height control RllO for desired height.
5.3 FOCUS ADJUST
Adjust focus control R122 for best overall focus of the picture. Usually the
center and corners of the screen do not focus at the same setting and a compromise
must be made.
5.4 CENTERING ADJUST
If the raster is not properly centered, it may be repositioned by rotating the
ring magnets behind the deflection yoke. The ring magnets should not be used to
offset the raster from its nominal center position because this degrades the
focus and resolution of the display and may cause neck shadow.
If the picture is tilted, rotate the entire yoke.
5.5 TROUBLESHOOTING GUIDE
Symptom
1.
Screen is dark
2.
Loss of Video
3.
Power consumption is
too high
Possible Remedy
Check l5V bus, Ql08, Ql07, CR2, CRl13
CRl14,
QlOl
Check horizontal drive waveform;
adjust horizontal linearity coil;
Ql07, Ql08
5-1