Ok, I tried everything suggested as well as all of the recommendations I got from WFCO tech support, nothing changed. Bottom line, Randy from bestconverter.com sent a replacement unit this past week which I installed. The flicker problem with the 12V
lights is virtually eliminated. There is still a bit of flicker on the 120v table lamp, but I can live with that since I dry camp almost exclusively.
Thanks to all who contributed their ideas to solve this problem (a special thanks to Randy for his help).