Newly replaced LCD screen was supposed to be brand new oem, not aftermarket, or made by anyone else other than oem manufacturer. The guy who did the work said he worked for BMW and MB for years doing just this work, replacing screens and other work fixing nav units.. He's saying that something must be wrong with the BM53 radio tuner, but the tuner had been working before, and I had just bought it new last month from Tischer - unit with the most recent part number, so I'm thinking that it must not be faulty.. any other suggestions, please let me know..