Bosch Dishwasher. hi, was thinking of buying a second hand bosch aquasensor dishwasher.. I think

Question

hi, was thinking of buying a second hand bosch aquasensor dishwasher.. I think the model is Bosch SGS46M78AU.. anyhow thw current owner says it needs 'minor electrical repair to circuit board' and when queried further said that sometimes it washed in normal time and at other times it took up to two hours. Any idea what the prob could be, and would it be costly to fix??Thanks!