GOOD NEWS. . . . The PICTURE UPLOAD FUNCTION IS WORKING !!! The tech folks at the parent company have been able to remedy the issue. You can upload pictures once again. Thank you for your patience.
I think bond-o is right as the numbers are 1 50 B, at least that's what it looks like to me.
The serial number looks like OB415926.
The drive should be vintage 1986.
Yep, it's an Alpha I. Here is a link to the free online manual if you don't have one. With a SN, you can be sure that some previous owner didn't change it to an older drive. It's been done, trust me.
Look at page 3 at this link.