The Challenger 4P is comprised of the OSI 502 (CPU) and 540 (video) cards. The Challenger 4PMF (mini-floppy) includes the OSI 505 (CPU), 527 (Memory), 540 (video), and A13 (disk connect) cards. Both have the OSI 542 (keyboard) and A15 (I/O panel).
Ohio Scientific Challenger 4P

































