Thank you for using Just Answer.
You seem to be able to reset the board for the machine by unplugging it. If the unit works correctly afterwards it points to either the board itself or a bad connection with a wiring harness or component.
You can dissassemble the board clean and inspect the board and all wiring and sometimes that will resolve the problem. I would reccomend this before considering purchasing a new board to resolve.
You would be looking at part number 2 on this diagram -
This should help with disassembly also.
Let me know if you need any more informaiton. I'll be back late tonight (10 pm eastern).