39-year-old Radio Shack laptop gets new CPU, keeps original screen 1

39-year-old Radio Shack laptop gets new CPU, keeps original screen

Posted Tuesday, Sep 27, 2022 by Jeff Safire

Hobbyist and IEEE editor Stephen Cass upgrades a broken laptop from 1983

by Benj Edwards, arsTECHNICA
Sept 23, 2022

TRS-80 Model 100

A 1983-era TRS-80 Model 100 as an action hero, dramatically exploding onto the scene.

Faced with a broken Radio Shack laptop from 1983, IEEE Spectrum editor Stephen Cass didn’t throw it away. Instead, he pulled out the logic board and replaced it with a modern microcontroller so he could control the vintage screen. Cass wrote about his adventure in detail for Spectrum last week.

Cass performed his operation on a Radio Shack TRS-80 Model 100—one of the first laptops ever produced—which features a one-piece “slate” form designed by Kyocera and released as the NEC PC-8201 in Japan. Its claim to fame was not only its small portable size (at 2 inches thick and 3.9 lbs), but having a great keyboard paired with its ability to run for up to 20 hours on four AA batteries.

The Model 100 included a 2.4 MHz Intel 80C85 CPU, 8 to 32K of RAM, and an eight-line, 40-character monochrome LCD with no backlight. It doesn’t sound like much compared to today’s portable beasts, but journalists loved the Model 100 because they could comfortably write stories on the go using its built-in text editor. It also included Microsoft BASIC, a terminal program, and an address book in ROM.

While some people upgrade Model 100s using new LCD screens and CPUs (keeping only the case and keyboard), Cass decided to attempt an interface with the portable’s vintage 240×64 pixel display. He found it particularly challenging because the computer handles driving the display in an unconventional way compared to today’s LCD panels.

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This article first appeared at arsTECHNICA on Sep 23, 2022.

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