The technician checked my refrigerator and decided the master control board needed to be replaced, and gave me the part number. I purchased the part he specified and he came back to install the new board. This did not fix the problem, I had him reinstall the original board, and he tried other things but could not fix it. Another service came a few weeks later and found that there was nothing wrong with the control board or the refrigerator. The evaporator had iced over preventing the fan from turning. Once defrosted the refrigerator has been fine. So I paid the first technician $800, which turned out to entirely wasted, and he is angry at me for calling the second service that showed his incompetence.