[llangard]

Me medio auto respondo por si puede ser de ayuda a alguien.

Buceando por internet he encontrado:

"There is one nasty catch though , when the transponder is switch off on the circuit panel there is a possibility that the mmsi code will be deleted resulting in no broadcasting whatsoever. When the device is switched off on the unit itself , the bue button , all is well.
The tricky part is that after such a delete you can easily re-program the mmsi again. It is a good thing you can re-install your mmsi , but it should not be swept away in the first place. Maybe something to warn Matsutec for"

O sea que parece que se puede solucionar, si no entiendo mal parece que hay que reiniciar con el botón azul (on/off) y reprogamar el mmsi. Parece que es más un bug del software que un defecto de hardware.

En cuanto pueda lo pruebo y os digo si me ha funcionado!