Crt Astigmatism And Geometry; Crt Vertical Centering And Trace Rotation; 3.2.7 Crt Horizontal Gain; Alignment Points - Motorola R-20010 Maintenance Manual

f
u
7
(!ml:3
f
VII
~
HORIZONTAL
POSITION
BASE CAL
VERTICAL
POSITION
36930-110
Figure 3-2. Scope Amplifier Board ( A2) - Alignment Points
3.2.4 CRT ASTIGMATISM AND GEOMETRY
1. Select Monitor function and Gen/Mon Mtr dis-
play on the System Analyzer. Set the Intensity
control for a medium-intense display.
2. While using the Focus control to maintain a
focused display at the center of the CRT , adjust
the Astigmatism and Geometry potentiometers
(Figure 3-2) for the best focus at the outer edges
of the CRT with minimum pincushion and barrel
distortion of the display. The two adjustments are
interactive ; to get the best display, alternate
repeated small adjustments between the two
potentiometers.
3.2.5 CRT VERTICAL CENTERING AND TRACE
ROTATION
1.
Select Gen/Mon Mt r display. Adjust the Intensity
control for a comfortable viewing brightness.
2. With the Test -Point Shorting Jumper, connect
TPl of the Scope Amplifier board (Figure 3-2) to
chassis ground.
3. Adjust t he Trace Rotation potentiometer (Figure
3-2) to make the horizontal trace on the CRT per-
pendicular to the graticule center line.
3-3
4. Adjust the Vertical Position potentiometer (Figure
3-2) so that the horizontal trace on the CRT passes
through the graticule center point.
5. Adjust the Trace Rotation potentiometer (Figure
3-2) to align the horizontal trace on the CRT
behind t he horizontal graticule line.
6. Remove the jumper from TPl.
3.2.6 CRT HORIZONTAL CENTERING
1. Select Gen/Mon Mtr display. Adjust the Intensity
control for a comfortable viewing brightness.
2. With t he Test-Point Shorting Jumper, connect
TP6 of the Scope Amplifier board (Figure 3-2) to
chassis ground.
3. Adjust the H orizontal Position potentiometer
(Figure 3-2) so that the vertical trace on the CRT
passes through the graticule center point.
4. Remove the jumper from TP6.
3.2.7 CRT HORIZONTAL GAIN
1. Connect the Mod Out port to the Ext Horiz port
on the System Analyzer's front panel.
2. Select Generate FM function and Scope DC dis-
play. Set the Horiz control for external horizontal