RV Replacement Generator Circuit Board 300-3056/3687 Dinosaur 300-3056/3687 Generator Power Supply Circuit Board; Replacement For Onan Generator Circuit Board Part Numbers 300-3056/ 300-3687/ 300-3687-01; Double Sided Plated Thru-Hole Technology Replacement Boards For ONAN Generators Made Using Double Sided Plated Thru-Hole Technology To Virtually Eliminate Intermittent Connections With Attached Wire Harness For Easy Installation