Number 34 appears on radio screen VX Calais

[Thumpin]

A friend of mine has a VX Calais and a number/code 34 has appeared on the radio screen. The volume still works but most other radio controls don't. The steering wheel mounted controls still work.
Weird problem. Even the on/off button won't work.
I've searched around but can't find much. Can any of the VX experts help?
Cheers

[Thumpin]

Just a follow-up. After disconnecting power to the radio unit and reconnecting, nothing on the radio worked.
However, whilst driving the car the radio would intermittently begin to work and then stop again. The owner removed the whole radio unit, disconnected all connecting wiring and shook the radio unit to see if anything seemed loose inside. Nothin sounded abnormal, so he put it back in and it immediately asked for the security code and now seems OK.
Maybe one of the multi-pin connectors was making a bad connection or something. Mystery!
Cheers