Initial problem was the oven/broiler turning off after being on for 15 to 20 seconds. Heating and Oven lights would then blink back and forth. Changed the thermostat, but did not fix the problem. Then replaced the Control Board. Now the oven/broiler heats to temperature and then shuts down with the Heating and Oven lights blinking back and forth and cooling fan running. Any suggestions on what could be causing this? Is it possible/probable that the new thermostat was defective? Thank you.