The symptom was only one channel through both the headphone and 7 pin. After investigating it turned out to be a dirty/loose connection on the head phone and the the 7 pin connector. He gave it a full check up and cleaning fixing the head phone. With the problem being the actual 7 pin connector, it was either another 7 pin or the coax. So I went for the coax. Figured the next thing to go would be my D8 and with the coax the SBM-1 might have a life after DAT.
Between chasing down the problems, check up, cleaning, and switching out the cable it ended up 1.5 hours labor ( @ 85 a hour ). So it was more than $40.