Checks so far: The condensor fan is running, the Evaporator fan is Running, and the Compressor is Running. The temperature in both compartments is room temperature, and suction pressure, when off, is 70 PSIG and goes down to 55 PSIG after running, which is about a 10-degree drop on the gauge.  Normally, when cooling, it would be about 5-6 psig when the freezer (evap coil) is at 10 deg F. Since the pressure is reading room temperature, it isn't cooling. I don't think it is low on refrigerant as it should be down around -5 psig if it were low.  Is it worth trying to add refrigerant to see if it starts cooling? 

I bought the refrigerator in 1989 and managed to keep it running. It seems to me that the compressor has finally gone out. What brand would you replace it with? I've kept this fridge going because the parts were basic and built ruggedly.  I know I can't buy something as good as this one. I don't have that many years left, so I'd like to buy something that lasts as long as I do. I'm on a fixed income and can't afford a lot of problems. Thank you for any help you can offer.