I have a GE GSS20IEMD WW side by side refrigerator. A few weeks ago the compressor started making a shuddering sound when it stopped running. I did the normal thing and ignored it. Now things in the top section of the freezer compartment are thawing. I removed everything and tried to evaluate what was working and what wasn't. When I pulled the fridge out, there was brown/black dried flaky gunk all over the bottom of the fridge and it looks like at some point some spilled over and went onto the floor before it dried. The drain is clear and clean. The compressor is running. The freon lines are cooling from the compressor. The thermostat seems to be working, the defroster is turning on and off by itself presumably properly. The evaporator coils are cooling and icing. Condenser and evaporator fans are running. However no water is coming out of the dispenser, (how this is related to the top of the freezer thawing I can't figure)
Do you think my problem is related to a defroster sensor?
And whats up with the water? Supply line is good.

Thanks for the reply, I did pull off the back cover and there was a normal amount of frost on the evap coils, I saw the heater kick on and let it defrost the ice, then the heater shut off. everything seemed to be working properly in that dept.
About a year and a half ago, I replaced the heater, thermostat, and motherboard. I'm not saying that it couldn't go bad again, I just think it would be unusual. Also I can't see what the motherboard would have to do with just the top of the freezer not getting cold. Seems to me that if the evap coils are getting cold the entire freezer would get cold. Of course I'm no expert.
Perhaps my evap fan isn't blowing properly? Its blowing, but slowly.