I have a non frost free M7065S Servis fridge freezer that is 3 years old. The fridge part does not cool but the freezer works fine. The compressor is running and is hot, but there is a strange “wind like ghost noise” every 5 seconds. There are also some white deposits around some of the copper pipes at the bottom near the compressor. The plastic pipe that comes out of the back is completely dry. It uses R134a.
I’m afraid it sounds like you have a system problem Dave 🙁
Either gas shortage, compressor failure or insulation. Any of these would probably deem the unit beyond economical repair.
If you need a definite diagnosis on this, a refrigeration engineer will be required with the correct test equipment, check repairs@ should you need one.
I have the exact same model with almost identical symptoms. When cleaning the fridge compartment I found a crack in the lining on the bottom right hand side just above the drain channel, oh well looks like this just 4 year old machine is headed for the tip!