It's been nearly 5 years since my last post on this blog; since I've retired I have more time to spend playing with scanners so I've unpacked my radios and set them up again. I'm anxious to get the Pro-2006 running again and see what I can still do with it.
A Pro-2006 with the OS-456 board recently sold in 2018 for $157... https://www.ebay.com/itm/Realistic-Pro-2006-w-full-os456-Control-Board-by-Optoelectronics/182988806921?hash=item2a9afb9b09:g:A1EAAOSwYxBaRoGO
A Pro-2035 with OS-535 board recently sold for $197... https://www.ebay.com/itm/Realistic-Pro-2035-With-OptoElectronics-OS-535-Computer-Control-Board/182873663506?hash=item2a941ea812:g:EmIAAOSwyi9Z-8h1
A Pro-2006 with an HB-232 interface sold for just $76... https://www.ebay.com/itm/Realistic-PRO-2006-Scanner-with-HB-232-Interface/173069030113?hash=item284bb7d2e1:g:UZUAAOSwnw9aSom5
Bare Pro-2006 scanners go anywhere from $70-100, so the premium for the Optoscan board seems to be about $50-75. Looks like there is still interest in computer controlling these scanners.