I went out to my 2008 Bounder model 35H. Turned on the Park radio button, and started the radio.

Then I turned off the breaker to the power converter via the breaker switch.
Then I went to the battery disconnect switch located above the entry door, and disconnected the Main Battery, nothing happened, as far as the radio goes.
Then I disconnected the auxiliary battery and the inside lights went off along with the radio.

Then I re-connected the main battery, and still nothing happened as far as the radio is concerned. But, when I re-connected the aux. battery, the lights came back on, and the radio too.
I hope that answers your question, or at least gives you a way of checking your system.