DEC VT420 User Manual

Troubleshooting and Testing 7
Table 2–1 (Cont.) Troubleshooting the VT420
Symptom Probable Cause Solution
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Screen Display Problems
Screen is off
center or rotated.
There is
interference from
electromagnetic
energy.
Adjust the screen by using the
Screen Align field in the Set-Up
Directory screen. On worldwide
models, you can also adjust the
screen rotation.
Terminal board. Replace the terminal board (3.3).
A horizontal
or vertical line
appears on the
screen.
CRT yoke harness
connector
Check and reconnect the connector
(3.2).
Terminal board. Replace the terminal board (3.3).
CRT/yoke/bezel
assembly.
Replace the CRT/yoke/bezel
assembly (3.2).
The screen
display is
distorted or
jittery.
There is electrical
interference from
nearby devices.
Move the terminal away from nearby
electrical devices.
The monitor is out
of alignment
Adjust the monitor (Chapter 4).
Terminal board. Replace the terminal board (3.3).
Replace the
CRT/yoke/bezel
assembly
Replace the CRT/yoke/bezel
assembly (3.2).
The screen
display does not
scroll. The hold
indicator is on.
The
F1
(
Scroll Lock
)
key was pressed.
Press
F1
(
Scroll Lock
) to
resume scrolling.
The terminal
appears locked
and does not
respond to data
from the host.
In the Set-Up Directory:
1. Select Clear Comm to clear the
terminal.
2. Select Reset to reset the
terminal.
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Section numbers follow the solution.

DEC VT420 Specifications

General

Brand	DEC
Model	VT420
Category	Touch terminals
Language	English