Need to know what the temp is on the back wall of both sides of the freezer... needs to be less than 10 degrees for the refer section to get below 40, but where are you measuring the refer temps? On the doors it can be 8+ degrees warmer than the top near the fins. Since you open the icemaker side more often than the other... frosting up is going to happen sooner. A lot of frost around the icemaker will actually insulate it but I doubt you are getting below 10 degrees.
I'd start by making sure your fans on the back running when it's warm out. While back there make sure there is a plug in the drain hose in the container near the flue.
Dang I miss my 1200.:B :B :B