Hello! I have recently acquired a JVC TD-V711, in excellent shape. When I try to adjust the PLAYBACK azimuth, I can't hear any difference at all! This is especially troubling, considering all the two head decks I have pronounce playback azimuth errors quite audibly. Pictured is the head block diagram, and the screw I am adjusting during playback. The service manual says that this is the playback azimuth adjustment screw. This is my first 3 head deck, am I doing something wrong here, entirely? Thanks!