Small freezer won't shut off
We have one of those little 3.1 cu. ft. freezers and it freezes well but runs constantly- it literally will not shut off. The seals around the door are in good shape.
The large black metal "ball", which I take to be the evaporator, gets very hot to the touch. I quit using it because I felt it might be a fire risk.
It appears to me that it's not reading the temperature, or there is a sticky relay. Is this worth fixing? Is it worth a service call or could it be a DIY job? I'm reasonably capable and might tackle it if I knew what to look for.
I've considered a workaround involving an external switch in the power supply, but don't know if it's worth it.
Comments greatly appreciated.