A new repair method applies to 90% of Technics Reel to Reel Decks. This unit is part of Ultimate series of recorders which sold extremely well because they were very good.
Also, because Technics advertised about them at length. And also because they do look as good as they do sound 😉
Most common is the RS-1500U original version which was named, or nicknamed, U38 in Japan, the U being the shape the tape takes when wrapped around the head-block and capstan, but Technics made quite a few variants, all in 3-speed flavor,