Thanks to Teeoster, you have actually answered one of my questions, which was whether the "S70F-12" was actually a C4. I am fortunate to have the diagram and parts list but was a little concerned because it makes no mention of c4, just the S70F-12. It will probably be at least a week before I get a chance to investigate, but I will post my findings in case anyone else can benefit. And, if I run into trouble I will take you up on a discussion. . . . will let you know. Thanks for putting in the effort to post the details!