Hi all. I have Kitchenaid electric range. It has issue with oven temperature control. When set to any desired temp it comes to that once and keeps showing same on display. The actual temperature after some time will fall but oven will not maintain temperature to set temperature. If oven is switched off and restarted again immediately, it will show the actual cavity temperature and start heating again but will lock again at set temperature but will not maintain set temperature again if monitored in the cavity. Any help please. Also if someone has service manual or tech sheet. That will be great help.