I think I found some promising info...haven't read through it all yet: https://ia801201.us.archive.org/23/items/DTIC_ADA038326/DTIC_ADA038326.pdf Here's photos of the reel: https://photos.app.goo.gl/u4UdDYc1RxYGTSh99 I see mention of a SEL 8600 computer. I wonder if this is for the SEL, or closer to the front-end? Kyle