The converter might NOT be blown, just over worked trying to charge failing batteries. I would get the batteries tested ASAP and then check the voltage the converter is supplying at the batteries. The converter should have been sized by the coach builder to run all the 12 volt systems and still charge the battery. Do you smell a burnt smell at the converter when it is running or does it just smell hot? Voltage should be a minimum of 13.2 volts at the batteries when charging. I would place a Volt Meter on the battery terminals and then have someone plug it in and see if the voltage rises, maybe not to 13+ volts, just takes a healthy jump. If it does, I would suspect the converter is still functional. With new batteries, you will have to keep an eye on it to make shue it will not over charge the batteries.
U. S. Navy (RETIRED) 1993
1995 Gulf Stream Scenic Cruiser 34' Diesel Pusher Cummins B5.9 12 Valve Engine, Allison MD-3060 6 Speed Transmission.
TOAD: 2019 Jeep Cherokee Trailhawk Elite
Road Master Sterling All-Terrain, Airforce One