4ch Dimmer - losing power communication

With the opportunity of this post I would like to wish all the best for all members of our C-bus community.

in a 7years old installation a dimmer unit is not working properly - probably came the time to be replaced...

I will try to describe the problem:
The 4ch dimmer unit is probably the most used unit of this installation since it operates the sitting room lights.
the last 10 days, every 10-15 minutes the unit loses the power and C-Bus indication lights while the channel indication lights remain ON. after couple seconds (4-10) the channel indication lights goes OFF, the 2 indications lights become ON again and the lights in those circuits goes off after 5 seconds since the restore option in disabled.

Since, there is no problem with the power supply - the channel indication lights remain ON while the 2 indication lights goes OFF, I believe that there is a internal fault in the unit.

PS1: The time between 2 looses of power was 10-15 minutes in the begging and as the days passes the time is shorter to 3-5 minutes yesterday.
PS2: After I enabled the restore option the lights does not goes off, ie the unit "understand" that it is loosing power supply.

Any ideas except of buying a new unit??