Hi, welcome to Just answer
How old is it and none of the rings work...correct ?
OK, the problem is with the terminal box of the main control board...you can take the hob out and turn it upside down to check the box and check the wiring connections...make sure nothing is burnt there.. then test the box
can you test the terminal box ?
OK, if you have removed the hob top off and there is nothing burnt then it is the main control board that is bad and will need replacement