[rickst29]

shared the 120v breaker (that's an input to the WFCO) with another 120v circuit, but there was nothing shared on output or split on output. The 12v output wire should have been wired directly to the WFCO circuit board (with 12v fuses), into one of the large "upstream lugs.

That circuit board is pretty reliable, and you can keep it. I do recommend, however, that you add another 120v circuit breaker, so that the "shared" 120v circuit connected by using the "hot" pigtail can have a breaker dedicated to that circuit, and a separate breaker dedicated to the new converter section.

You need only replace the Converter section, and not the 12-VDC circuit board. The original Converter section you have is identical to the one they installed OEM in my 2619 from very late within model year "2006". Mine blew up long ago. The new "replacement" WFCO units are somewhat better than the originals, but not as good as the USA-designed and USA-BUILT replacements from progressive dynamics. The PD units are much more costly. (And they are worth it, IMO.)

Buy from factory-authorized "bestconverter.com", although its owner will try to tell you that their own "Boondocker" replacements are just as good as PD. They're not (or definitely were not, when I bought and used one for a few years before upgrading a second time to PD).