The Scisys Chess Champion Delta-1 is the same model as the Novag Chess Champion Delta-1, which is much more numerous. With the Chess Champion Pocket Chess, Chess Partner 2000 and Chess Champion Super System III the Delta-1 was one of the chess computers released by both Novag and SciSys at the same time. The SciSys Delta-1 examples can be identified by the stickers added to the boxes and manuals (see photos below).
There are similarities between the PCB components of the Delta-1 and those of the Novag Chess Champion Mk I and it is possible that release of the Delta-1 was held back pending the result of the CompuChess copyright court case and appeal (see SciSys and Novag: The Early Years). That might explain why the manuals and boxes are dated 1979 yet the chess computers were not released for sale until late 1980.
With a current Wiki Active Chess rating of only 657 Elo the Delta-1 props up the Active table. The rating is close to that of the Novag Chess Champion Mk I rating of 720 Elo but recent (2019/20) examination of the computer code suggests that a different programmer was partly or entirely responsible. See this thread on Schachcomputer.info (link). Guessing the programmer(s) certainly has been a puzzle up to now. From respected internet sources you can currently chose between David Lindsay (Schachcomputer.info), Peter Jennings (Spacious Mind), and David Levy? (Hein Veldhuis). However it now seems clear that the Delta-1 program is a pirated copy of David Lindsay’s Applied Concepts Boris program (rev.1), with bungled alterations to adapt the program and possibly disguise it’s source?
Those were certainly interesting days for chess computer programming and manufacturing.