GDM 49F First tech diagnosed defective compressor, drawing lock rotor. When I arrive the unit is running with no product, temp is 0 degrees. 20 degrees across evap. Pulled rack out and amped compressor, 3.4 amps. compressor rated 9.9. Called tech support and was advised to replaced compressor which was already on site along with start kit and drier. When i adjusted ORI valve the compressor would start pulling into a vacuum at about 4 amps. Ambient in store about 75 degrees. Pressures 404a 200 over 10. Superheat would vary from 50 degrees to 5 degrees very quickly. Replaced compressor and other components, exact same results. Called tech support and was advised to cut 3 inched off both cap tubes at liquid line, I did this and purged with nitrogen, could not detect any restriction. ii vacuumed to 200 microns, charged, no change. Now they want me to replace complete cap tube assembly. This unit is still under warranty. Question, if a cap tube was restricted wouldn't I see an elevated head? I'm not a refrigeration guru but have a considerable amount of experience over the years. Another question is that the evaporator fans cycle with the temp control?? According to the schematic the only things that cycle the fans are the door switches and the defrost control. Last thing this a national account and are only paying us $250 for the compressor change out. I exceded that by a considerable amount and a new unit would only cost about $4000. I always get stuck in these situations. Any suggestions would be appreciated.