okay. the problem is the relay board controls the digital readout but can still run the oven okay because that is controlled by the relays. but the transformer on the board also controls the relays so when its closing the relay for back its loosing power to the digital readout. my suggestion is to replace the relay board. heres a link to the part.
http://www.repairclinic.com/PartDetail/Relay-Board/9782437/940113?modelNumber=YKERC607HB8 thanks and best wishes, Bryan