EX-2200-c restart interfaces every few seconds

Hi, My first post here.

I'm italian and working with juniper devices. I got an issue with a EX2200-C.

COM and MGMT interfaces works, but the 12 ethernet interfaces go down e restart every 10/15 seconds. So it is unusable.

I've tried every configuration, and different firmwares, nothing change.

Please help me.

Thanks, regards