GE freezer help?

I have a "GE Profile Bottom Freezer" appliance. I have had it for around a year. Starting at the beginning of the summer, the freezer has not cooled fully while the fridge has been fine. I have had a technician come twice and both times he has had said the problem was that the condenser fan was not running and his solution to this was to replace the circuit board. This however has not solved the problem wither time. I have done some research and found that other people with similar problems have had problems with the pipes getting clogged with ice. So I defrosted the system. This did not resolve the problem. Does anyone know what the problem may be and how to fix it?