Hey Bob,
My understanding was the WFCO's were prone to dc main board failure. I was able to pick one up off ebay for a spare, 51.00 shipped. May be faster and easier than troubleshooting at the component level. I don't suppose you have a real schematic, do you? Were you plugged in when it failed or just showed up DOA out of storage? If you have 120 @ the transformer primary, look for a blown rectifier (diode) after the trans. secondary windings. If they let their smoke out, they are done and you can see it.
If you were "live" when it failed also look for a thermal-fuse
McDave
PS also check the breaker that runs converter, of course.