Clearly your converter isn't doing anything at the moment, or a fuse blew between it and your 12V distribution panel. It should be pretty straightforward to troubleshoot with a voltmeter: do you have 120VAC at the converter input? Is there 12VDC at its output terminals? Does it have any fuses on it that are blown?
My guess is that you'll need a new converter. It's possible too if it put out a high voltage spike in the 12V system that some 12V appliances are also damaged...but you can't really check that until you have a working converter or a charged 12V battery hooked up.