DEC VT420 Service Manual page 16

8 Troubleshooting and Testing
Table 2–1 (Cont.) Troubleshooting the VT420
Symptom
Screen Display Problems
The screen is
blank, except for
the blinking block
cursor in the
lower-right corner.
The screen has
been inactive for
one-half hour.
Phosphor retains
an imprint of
characters on the
screen when the
monitor is turned
off.
Character Display Problems
In local mode,
the screen
displays different
characters than
those typed.
Section numbers follow the solution.
Probable Cause
CRT saver feature
is activated.
CRT/yoke/bezel
assembly.
Alternate
character set
selected.
Worldwide only:
Wrong keyboard
language selected.
Keyboard.
Terminal board.
Solution
Press any key to restore the screen
display.
Replace the CRT/yoke/bezel
assembly (3.2).
Clear by selecting the Reset field in
the Set-Up Directory.
Check the keyboard language
feature in the Set-Up Directory.
Replace the keyboard (3.4).
Replace the terminal board (3.3).