I have changed the electronic clock/oven timer twice. The 1st one last 2 months and may be due to electrical surge it got burned. Changed the second time, this time clock was working fine, did not turn the oven on. couple of days later tried to turn the oven on and nothing worked. the board displayed f15 and some time f99. the time clock wont even work now. I turned the electric off for 10 minutes. the board beeps and displays F15/F99. top cooking range works fine. I did not changed the plastic which goes on top of the control timer. Please help me. I have difficulty to believe that the second board is bad or got burned during the process. could there be any thing else bad or need to be replaced. Thanks.