Ht2000 keeps rebooting

A few days ago I turned on the power to my ht1100 and it remained dark. I called support and after some diagnosis they sent me an ht2000. After an hour of power the lights would come on for 10 seconds  then off for 30 ad infinitum. Tried it several times, same thing.

       Support sent me a second modum same thing. Today after speaking with support they are sending a third modem. I'm thinking unless this is  common failure something else is likely the problem. Mabe the antenna or coax, a short? Don't  see how, but what do I know, lol. Just looking for a little guidance.

Thanks,

Bill