Thanks to all. Had found converter. Checked where it plugs in with trouble light ... 'shore' power getting to converter (& also checked fuses on converter and they are good).
At the moment I'm not sure 12 volt power coming out of converter (haven't had chance to test any lately).
Will try the neg. ground disconnect as suggested to see if converter outputting 12 volts. Suspect converter needs replacing, but also possible that the 'BRIT' switch (shore vs. generator vs. battery) got fried.
The .pdf manuals, comments, etc., have been helpful folks!
Hope to work on it this weekend.