Are you sure the compressor went out and it not the start component that went bad?
While everything is fixable, I guess you have to weight the cost of repair vs replacing the entire unit.
What you would need to do is you have have to get the Make and MN# off the compressor and who made it. Chances are a good refrigeration shop can "possibly" cross the compressor to a newer one that will work. However, the start components will need to be replaced and probably the expansion valve as I dont know what type of refrigerant is in this old freezer. So again you have to weight the cost of repair vs just replacing the entire unit. It would be cheaper to replace the entire unit as a whole. But I guess if there is a personal attachment to it for whatever reason. Then you will need to contact a reputable company that can repair this. I would stay away from a appliance repair as your going to need a guy who can think outside of the box to get this thing back in working order. You would be probably better off calling a heating and cooling company that does both residential and comerical application, including restaurants. Your going to pay an arm and a leg. Well over 1000 bucks.
On a side note here did you ohm out the compressor? That would tell you of its dead. Check you tube on how to ohm a compressor. That free and all you need is a voltmeter and some basic hand tools. If the compressor check out good after ohming, then you need to look at the start components which could just be as simple as failed potienal relay or a bad capacitor. You dont need OEM you just need to get the specs off the old part as far as voltage. Just some food for thought . The other things that could be bad is the temperature controller, or defrost time.
former hvac tech