WX1000+ Stormscope problem

I recently got an L3 Avionics (ex BFGoodrich) WX1000+ stormscope installed.
http://www.as.l-3com.com/products/wx1000.aspx

It is second hand but it got all the checks and forms by the avionics vender
including being sent to L3 avionics for re-certification papework just
before installation.

The Avionics shop which installed it in Europe is EASA Part 145 approved and
did very good work but its away from my country and I would have to fly the
aircraft there again for checks.

The problem is that the WX unit reboots on its own every few minutes (5~10)
displaying the intro. screen again.
No error reports, nothing, just a restart as if I had switched it off and on
again and then as soon as I choose the operation mode (120* or 360*) it
functions properly.

Has it happened to any of you that owns an aircraft with such a stormscope ?
Possible reason ?
Possible remedies ?