IBM 3270 Maintenance Manual page 195

3-300-12
1. Remove the serial port wrap plug from the
Keyboard/Timer adapter.
2. If you removed a serial port device earlier in
this procedure, reconnect it.
3. Press Enter to continue testing.
XX:XX:XX
ERROR -
KEYBOARD/TIMER 3XX S
DID YOU RECEIVE A 3XX ERROR
MESSAGE?
YES
Go to "Keyboard Diagnostic Error Codes"
on page 3-300-14.
NO
Maintenance Information