My 1980 30' Catalina has an old fridge ( the only ID on it is NP) that has worked well until now but suddenly stopped cooling. The compressor runs and the housing it is in gets hot. The condensor radiator fan runs too. A quick push on the bicycle type vent gave me a puff of what is probably freon ( because of it's age) so there is gas in the system. But it doesn't cool. There is a drier/filter in the liquid line and I wonder if that is the problem, ie, filter plugged. Does anyone have any thoughts on this problem. Canukwi.