Clock/timer not working. Diplomat gas oven?

Tried to change the time on my oven and can not get it to respond. Have unplugged and left it for several hours, pressed cook start and cook stop buttons simultaneously, pressed + and - buttons to reset time, nothing. Just flashing display with 0.00 and A showing. Consequently cannot use oven, can the clock be by-passed?

Dilly
March 2010