Relay WP9752759

How to test relay part # wp9752759

On our combo unit, the microwave works fine but when using the main oven, it will heat-up to the desired temp then begin to lose heat. The display continues to show the correct temperature but after about fifteen minutes, if the oven is quickly restarted, it will then display the current correct temp which will have dropped precipitously (about 55 degrees in fifteen minutes). In other words, if i am baking cookies at 350, the oven preheats normally and everything appears good. I slide the cookies into the oven and the display continues to read 350. After about fifteen minutes, if i push the bake button, the display will change to the actual temperature (about 295) and i have to cancel the bake and completely start over again to re-reach the desired temperature. I have already replaced the temp control and the thermo fix but to no avail. My next purchase is the controller (ps11752703), at $400.00. Does this sound to you like it will solve my problem?

Your last response did not fulfill its intended purpose. As i stated in the first sentence of my last question, the oven works like normal in the preheat mode; meaning, the bake and broil elements work just dandy! It is at this point, however, the oven begins to lose heat and has to be restarted in order that it re-attain the desired temperature, this despite the fact the control continues to display the set temp and not the actual temp. I was told by another company that my thermostat must be bad, and they sold me an expensive temperature control probe. That did not solve the problem (i did not think it would as the oven does seem aware of its temperature, despite not being able to maintain it). I also replaced the thermo fix module based solely on the part description, and that did not work. So what's next? I figure it has to be the control board, right? Please advise.