Refrigerator section set at 42 and actual temp got down to 28. cold enough to freeze water reservoir. defrosted reservoir and changed thermistor. did not help. dispenses water now though. try to dispense ice or crushed and sometimes there is no response at all, sometimes it works for several hours. changed the air damper behind crispers and made sure condenser was clean. while set on 42, it held at 38 for about 18 hours but now already down to 33. Does this sound like a control board issue?