This message is displayed when there is a communication fault between
the CPU board and the VDSIB during system start-up.

The following procedure is applicable also if the keyboard locks during
system start-up as HW and SW versions are displayed.

Check on the Power HUB board (A21) the LEDs H1, H2, H3 and H4
status; they should be all ON.

If LED H1 is OFF, disconnect the cable X84-X75 (X84 side) and verify if
the LED switch ON; if it doesn't light change the cable (there is likely a
short circuit between the cable pins), otherwise replace the Power HUB
board.

If one of the other LEDs is OFF, replace the Power HUB board.

If all the LEDs of the Power HUB board are ON, check the connections on
the VDSIB board, mainly the cable X84-X75 (X75 side); if necessary
replace the faulty cable.

Otherwise, the problem can be related to a bad synchronization of the
VDSIB board, in this case:

1. Switch OFF the unit
2. Disconnect all the VDSIB cables
3. Turn ON the unit
4. Reconnect the VDSIB cables
5. Switch OFF the unit and ON again to reboot the system and restore
communication.

If the problem is still present, replace the VDSIB board.