It is an old whirpool built in double oven. It has three timers - the one on the far left is a regular cooking timer, the other two are a start timer and stop timer. The buttons on the start timer and stop timer push in and pull out. they also turn. Sometimes the start and stop buttons get either pushed in or pulled out in such a way that the top over won't turn on. We can't find the manual to see how to correct this problem so we can use the top oven.