Looks to me like your Concertone is defective.... If under warranty, have it replaced. They replaced mine once.
If warranty is out, well you're out of luck.
Option 1 - Buy a replacement unit (can be costly...)
Option 2 - Buy an inexpensive DVD player (and use the HDMI connector instead, if your TV has such a connector)
Option 3 - Stop watching movies while camping and enjoy the outdoors