All knobs (A+B did not work), RCA inputs/outputs (pre out not tested), FM reception, headphone output and speaker outputs have been tested and are working. All function, tuner, source direct, adapter and source direct buttons are tested and working as well. I did not hear a difference when the turnover, subsonic filter, loudness and cartridge buttons were engaged. The side panels have wear and deterioration. There is general wear and internal dust. If you have any requests or questions, ask before purchasing. Requests to remove packing slips or invoices will be ignored.