Cable box and the Cable wire are hot, replaced the box today and the new one is also getting hot

I had Comcast send a tech, he snipped off both ends of the Coax and that solved the problem, it's been fine since. Of course Comcast cxharged me $40.00 for the tech visit and I had to spend time convincing them to credit the charge which they did. The rep i was on line chatting with told me every tech visit is billable 

This is excessive heat.  Comcast sent us a message to unplug the box, that's how we knew it was so hot. We could barely touch it to unplug. We replaced the box but it still ran hot.  Comcast advised it may be the COAX but we troubleshot the box with the COAX in another cable outlet and it was fine. We are waiting for our availabilithy this week so we can schedule a tech  Thank YOU

Thanks for the reply, we have Comcast appt for this Thursday for them to look at the issue 

I don't know how the coax would cause it, maybe its really bad wiring and the box is working way harder than usual to decode the weak signal. It might also be that the sun is shining through a window onto the box making it get really hot. I can't think of any other reason why both boxes would be getting that hot.

does the wireless box have a shut off mode if the wireless box gets to hot