Hi Mr.Dave, I am Max from Italy and I am a technician. At the moment I am searching for tutorials or service manuals about DDS2-3 and AIT1-2-3 like the SONY SDT-7000, SDT-9000, SDT-10000 and SONY SDX-300C, SDX-400C, SDX-500C but with no results!! I strongly need these documentations, because i must repair these DAT units. Helicoidal scan technology is used in these devices and our clients use those under SCO OPEN SERVER 5.0.4. I have already requested this material from SONY, but their answer has been negative.