Vt420 Self-Test Chart - DEC VT420 Service Manual

12 Troubleshooting and Testing
• Set the terminal to
VT100 mode, you can press
Chapter 5 for a description on using set-up.
Table 2–2 VT420 Self-Test Chart
Self-Test
Power-up
Selected while the
VT420 is operating.
RS-232 port data lines
loopback†
RS-232 port control lines
loopback†
Printer port loopback
DEC-423 port loopback
Screen alignment pattern
Run all above tests, except
screen alignment pattern.
Do not type spaces between the characters in any escape (ESC) sequence. The sequences
are shown with spaces for clarity only.
† Worldwide models only.
in the General Set-Up screen. In
VT100 Mode
to generate an ESC character. See
F11
Prerequisites
None
Set-up
– Local mode
RS-232 loopback connector
RS-232 loopback connector
DEC-423 port loopback
connector
DEC-423 port loopback
connector
Set-up
– Local mode
See individual tests. All
loopback connectors must be
connected.
Sequence
Turn the
terminal on.
Once:
ESC [ 4 ; 1 y
Continuously:
ESC [ 4 ; 1 ; 9 y
Once:
ESC [ 4 ; 2 y
Continuously:
ESC [ 4 ; 2 ; 9 y
Once:
ESC [ 4 ; 6 y
Continuously:
ESC [ 4 ; 6 ; 9 y
Once:
ESC [ 4 ; 3 y
Continuously:
ESC [ 4 ; 3 ; 9 y
Once:
ESC [ 4 ; 7 y
Continuously:
ESC [ 4 ; 7 ; 9 y
ESC 8
Once:
ESC [ 4 ; 0 y
Continuously:
ESC [ 4 ; 0 ; 9 y