Long before Philips came out with a dictating machine cartridge which became popular as the Cassette, RCA had these cartridges. When he switched it into Stop, then Rewind, it would run. Mine worked just like it should, and it never smoked. The Akai 4000 was a good general purpose 3-head deck. This Akai X-200D was a very good machine.
Most decks apply the bias to the record head.
This type of deck applied only audio to the recording head. Another head was placed on the opposite side of the tape, and applied the bias to the tape directly. These standard test tapes were used to check the alignment and overall performance of tape decks. This old Webcor wire recorder was made by Webster-Chicago. Wire was a good enough recording medium, but handling that much fine steel wire was rather inconvenient.