Terry Stewart's (Tezza's) Classic Computer Collection

Ohio Scientific Challenger 1P and 4P

(Note: Click the images for larger views. I also describe these machines in a YouTube video(now in HD!))

OS Challenger 1P playing blackjack!Challenger 1P

This functional-looking micro gained a small but loyal following amongst hobbyist and engineers. Based on the 6502 chip, it came in a sturdy steel case with a full stroke keyboard and included 8K Microsoft BASIC in ROM with Petscii-style graphics. A 22-character/line mono screen was bound to have limited its usefulness to learning BASIC, perhaps some interfacing and "programmable calculator"-type tasks. However for these things, it was an economical computing solution.

Apart from the Dick Smith System 80 you could say this was the first computer in my collection. It was given to me in 1987 or so by a guy whose university department was about to junk it. I think it had been used to teach engineering students BASIC programming.

Although this model was fully clothed (i.e. enclosed in a case with keyboard) when launched in 1979, it is just one step above what could be cobbled together by an enthusiast with a soldering iron. In fact, its predecessors from Ohio Scientific were single-board kits and the unit itself has the appearance of an assembled kit.

When I was given the machine I also got the manuals and a book. To today's eyes the manuals are distinctly amateurish, consisting of typed and annoted pages on photocopy paper. They also assume users are somewhat familiar with electronics and the concepts of digital logic. Much of it is beyond me! For 1979 though, when the electronic hobbyist was the main market for these micros, such documentation was not that unusual.

This particular CP1 originally had a RAM issue. When first dragged out of the wardrobe it had been languishing in for years and switched on, the available memory showed only 2.5 KB when it should have been 8 KB. It's all good now though. Furthermore, I've found some programs to keep it company !

Challenger 4PChallenger 4P

The 4P was acquired much later than the C1P above. It was gifted with other Ohio Scientific gear in 2013. I love the walnut wood sides! You can see a family resemblence to the 1P but the 4P has some serious features. A 64 column screen, colour capability and more ports and interfaces than you can swing a cat at!

Originally this particular cassette-based unit had a mere 8k in RAM (Read about the CP4 aquisition here) but Retrochallenge 2014 SC saw this expanded to 32k, and a demo program written to show the computer off. In a previous life the C4P was fitted for disk. I do have the disk board and the appropriate drive, and hope someday to bring the machine back to its former glory! In the meantime, it shares a prime spot in the collection with its junior sibling!

The Challengers are great little working units to have. When I fired it up the Challenger 1P after years of inactivity I was amazed that it actually went at all! Discovering that I actually had more than one working vintage computer got me started on collecting a few more.

Update: The Challenger 1P and 4P are no longer with me. They have been passed on to those familiar with OSI tech. They should be well-looked after.

Want to know more about this micro? Google is your friend.

This page last edited 8th October, 2021

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