I have an older GE electric JSP26GN range. The oven will not heat up. When I set a bake temperature the indicator changes to 100 degrees for about a minute and then just goes off. The same thing happens with turning on the broiler. I have played with the it a few times and have actually gotten it to start heating so I know the elements are still working but it will not stay on. From what I have found on the internet it looks like I need to replace either the Control panel, the Relay circuit board or the Oven Clock but I do not know which one, and since replacing all three is about the same price as a new range I would like some advice on which is the likely problem. The clock and all the burners are working.

Thanks.