I'm curious of your word BUSS. I think you are referring to a black circuit breaker in the AC side of the power panel. This may be the circuit breaker feeding your converter/charger unit. If it is bad then you may not be getting 120VAC going to the converter which would also result in NOT getting DC voltage to your circuits.
However both the the converter and the working battery both feed the same point on the 12VDC distribution panel. If the converter is bad the 12VDC then can be feed from the battery. I am guessing your battery may be run down as well and may also have to be replaced. Once you run a battery down below 50% charge and not recharge back up in a timely manner then it may also be bad and need replaced...
First you need to determine if you are feeding 120VAC to your converter/charger unit. Once you are feeding 120VAC to converter then maybe the resulting DC coming from the converter will solve your other problems.
Hopefully the battery will recharge as well but chances are it may not come to back to life.
This is where a multimeter is a very helpful item to have around the RV TRAILERS and know how to use them.
Here is a simplified wiring configuration for the 30A RV Trailers that might give some clues on what may be missing.
Roy Ken