Thank you for your question on the Skybox not cooling.
When I first saw these when they came out I thought they were really cool. Since then my opinion has changed.
These units ended up to be non-serviceable with the sealed system. The manufacturer does not even list the sealed system parts in the parts diagram.
The only thing I can suggest is to check to make sure the temperature control is working.
If the compressor is not running then I would say it is not repairable.
What I have discovered is that if the unit is set at the very highest setting on the control it would slowly ice up and you would get no airflow across the evaporator and stop cooling.
If that is the problem I would let it sit with the door open a couple of days to let it thaw out and then set the control for about mid-point.
If the sealed system with the compressor is not working then it is not repairable.
Most technicians will not want to work on these because of the complicated mechanism that you have to remove to get at the inside components.
If you would unplug the unit and open the control box on the temperature control and use a meter to check the cold control for continuity.
If it checks out okay then and the compressor is not running, as much as I hate to say it is non-repairable unit.
Please let me know what you find out and decide to do.