Hello Daryl,
hope you don't mind me stepping into this post/conversation. I recently purchased an H&W autocollimator and as far as I can tell it is the same model than yours. It is in good (and working conditions), but I do not have the power unit. I only found a picture from 1959 with the title 'Autocollimator with remote electronic indicator_1959' showing the autocollimator and your supply unit. It would be great to figure out what type of voltage (AC/DC) and level the photooptic cell needs and what it returns to drive the meter on the supply unit. With this information it should be easy to build something new and make it work. Unfortunately I can't see the posted pictures clearly. Would you mind to share them? My autocollimator has no model or serial number on it, but it seems to be a TA-3 or TA-4. I can soon offer a copy of the original manual from 1960, which I found on eBay and would like to convert to PDF. Hope you still have your unit and I could help with the manual, since this post is from 2002. Would very much appreciate to get in contact.
Best,
Peter