I'd say you got a lot of good use out of a 1968 oven; time to admit defeat and buy a new one.
When repairing any electrical appliance, you should only use parts made for that appliance and approved by the Manufacturer. This is especially true with any electrical heating type appliance, furnaces, water heaters, stoves, cooktops, ovens, and even hair dryers. Using replacement parts that have not been evaluated for use with the appliance being repaired can be dangerous; and, it can void the listing for that appliance.
Most people don’t understand how important the listing and labeling of appliances, electrical devices, electrical fittings & wiring, gas appliances, and even things you don’t often think about, from heating ducts to x-ray equipment really is. A listed product has been evaluated to meet certain Standards, written by various agencies, or by Nationally Recognized Testing Laboratories (NRTLs). These products are then subject to random testing (by the NRTL who has listed that product) during production, to be certain that the Standard is being maintained.
Altering a listed product in any way can void the listing, as it was not evaluated to perform safely in its altered condition.
Two of the first NRTLs, also known as Independent Testing Agencies, or as Independent Third Party Testing Agencies, were Underwriters Laboratory, and ETL (first known as the Lamp Testing Bureau of the Edison Electric Illuminating Company, then, two years later renamed Electrical Testing Laboratories). As the UL name implies, insurance companies were involved in the evolution of these labs. As the use of electrical power was starting to spread, about the time of the Chicago World’s Fair in 1893, insurance companies began to wonder how safe electricity was. UL was founded in Chicago in 1894, and has been evaluating products (not just electrical products) for safety ever since. Edison changed the name of his company to correspond with the variety of other electrical products coming onto the market. The job of these labs was to determine ways to consistently tell if a product would be safe to use, and how the product was to be used. When used improperly, or altered from their original form, insurance companies have a right to proportion the damages they pay out. Some, or all, of the damages may be placed on the party who altered the product, or installed it in a way or for a purpose that it was not intended for.
Now, let me apologize for the sermon/history lesson; and again, let me urge you to accept the fact that 40 years is a good, long life for an oven.
Today, there are around 20 NRTLs recognized by OSHA; and they are all looking at you, whenever you violate a Standard, or alter a product. Scary, huh?
Answered By: Electrical Inspector - 5/15/2008