Not cooling properley

Seems like you could have a problem with your Defrost system. This video should help you out with diagnostics. It is not your exact model number however it is very similar in operation. When you remove the back panel make sure you have frost over the entire coil. If your evaporator is only frosted along the top or in the corner you will likely have a refrigerant leak or an inefficient compressor. If this is the case it would be cheaper to replace the unit than repair it. Hope this helps.

If you have an even frost pattern across the evaporator coil this indicates a part of your defrost system defective. If you have just a partial frost build up on the evaporator you have a sealed system issue. A sealed system would mean you have a weak compressor suction valve or evaporator leak. In either case it would not be cost effective on this unit due to the age . If you have an even frost pattern that is telling us a defrost issue , I would defrost the coil and do a continuity test on the defrost heater. If the heater has continuity that means it is good, I would then replace the defrost timer & defrost thermostat. See parts breakdown below . Matt Ace technician

Hello
This is a self defrosting freezer. It has a defrost system on it. Do you have frost on the back evaporator coil ? Matt Ace technician