I have a fellow tapers SBM-1 open at my house. The RCA jacks need to be replaced. I called one of the people I know that has worked on Sony gear. He no longer had his parts manual, so he didn't have the part number. He gave me Sony's direct number for service parts.
I called and told them I didn't have a part number, but told them what I was looking for, they looked up the part number for me and their computer system told them the part was no longer available. I asked if that was true for all internal parts on the SBM-1, she then proceeded to look up two more parts from the service manual. Both of those were also listed as no longer available.
Looks like if you have a SBM-1 and need parts for it, you're going to have a tough time getting them. We all knew the hammer would fall, it was just a matter of time. Looks like that time has finally come. :-(
RIP.
Wayne