Just had this problem for the first time this past weekend. No 12 volt power supply. Battery checks with 12 plus volts, inline fuse at battery good, both fuses in power converter good. I have power to everything as long as shore power is connected but once unplugged nothing works. Any suggestions? Thanks for the help. This is a CF32BL.
I would follow the known power trail. Start at the battery and check all the wires and connection to the converter. You say the converter fuses are good but what about at the fuse connection. One prong should have 12v. It may be a bad converter. It also could be just a loose connection somewhere. I would guess the problem is somewhere between the converter back to the battery. How are the landing legs? I think they are separate from the converter and connected directly to the battery.
Don't know if you are having the same problem but I had issues with the ground from the battery. Mine was intermittent and I was convinced the wire was either pinched or had a bad splice some where. After several attempts at tracing the wire including dropping part of the fabric on the underside of the trailer (mine is a BL as well) I found that there is a ground junction block mounted under the converter/power distribution panel. If you are looking for it you might be able to see it with the water heater and pump access cover removed. I had to actually loosen the converter/power distribution panel to get at mine. Looked like the ground from the battery had never been tightened.