Probably not very useful but my mark I serial number is in the 200's. I dont know when the mkII started.
The only switches I could imagine would be either a USB/rca input switch (does it have a USB input?) or a phone mm/mc switch, if the preamp is a ta-2000 with phono.
The only switches I could imagine would be either a USB/rca input switch (does it have a USB input?) or a phone mm/mc switch, if the preamp is a ta-2000 with phono.