Screen Control; Subcontrast; Rotation - DEC VT420 Service Manual

4.2.3 Screen Control

To adjust the screen control:
1. On the front of terminal, set the brightness control to maximum and
the contrast control to minimum.
2. Adjust the screen control (R657) until the white background (raster)
almost disappears, but is still visible.
3. Readjust the brightness control to the user's preference.

4.2.4 Subcontrast

To adjust the subcontrast control:
1. Display the alignment pattern of E's (Section 4.2.2).
2. Set the contrast control on the front of the terminal to maximum.
3. Turn the brightness control on the right side of the terminal until the
raster just disappears.
4. Adjust the SUB CONTRAST control (R647) to the maximum intensity,
maintaining the focus of screen characters.
5. Readjust the contrast control to the user's preference.

4.2.5 Rotation

Worldwide Model
To adjust the rotation:
1. Recall the default settings for the terminal by using the
in the Set-Up Directory.
2. Adjust the rotation by using the
Directory.
North American Model
To adjust the rotation:
1. Display the alignment pattern of E's (Section 4.2.2).
WARNING
The next step exposes you to the CRT anode, which stores a
high voltage. Use caution when working this area.
2. Loosen the yoke clamp screw on the CRT neck (Figure 4–5).
Adjusting The Video Monitor 47
field in the Set-Up
Screen Align
field
Default