Yes I've opened up and repaired several of them
Those large ceramic resisters are simply bleeders for the input stage filter caps. They do get a bit warm and are placed near some temperature sensitive components - an easy fix
Happy to pay shipping costs to get your defective WFCO here - always collecting them and can always use more spare parts
Schematics and parts lists are available for all of the converters
Yes they do make a great bench supply
Get your ESR meter (NOT a standard cap value meter but a proper ESR meter) and check the caps - sure bet one or more has gone south