I just had this happen on my 2017 freedom elite where the radio was seemingly dead.
I hadn't use the RV and there is a switch in the breaker panel to turn on the converter to charge the 12v system when on shorepower. Needless to say the switch was off and leaving on the lights and stereo the coach battery drained.
Either way I got it charged back up and that's when I noticed the dash stereo didn't work. I ended up pulling the stereo out and unplugging it all together and plugged it back in and it worked.
On a stereo there are 2 positive wires. One for constant power and the other to tell it to turn off and on. One must be hot all the time and the other on a switch for the coach. I guess draining the battery caused it to hang up some how and pulling out the plug from the back of the stereo reset everything. I guess just disconnecting the battery might do the same thing. I also think it maybe possible it is also hooked to the chassis battery but that would be odd.
Hope this helps.
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