Replacing a Amstrad PPC640 Monochrome LCD with a Modern Color LCD

The Amstrad PPC512 and Amstrad PPC640 were portable computers released in 1988. They were the first IBM PC-compatible computers produced by the United Kingdom-based electronics company. Their goal was the build the most affordable PCs possible. If you’re thinking “laptop,” then you’re mistaken. These were essentially desktop computers with a monitor and keyboard attached with hinges, and a car battery that was good for an hour of use. The monitor was a sad 9” monochrome LCD that is to modern Retina screens as the Ford Model T is to a Ferrari 488. That’s why Drygol of retrohax.net decided to replace that LCD with a modern full-color LCD.

The only difference between the Amstrad PPC512 and PPC640 was that the latter had a tiny bit more memory, a speedy 1200 baud modem, and came in a breathtaking shade of gray. Drygol has the PPC640, and the LCD screen was damaged in one corner. That was obviously unacceptable, and so Drygol decided to replace it. A modern (ish) TV with a 9” color LCD that has a 4:3 aspect ratio that was procured through eBay seemed like a great replacement option, Drygol just had to find a way to make it work.

They started by disassembling the Amstrad PPC640, and then gave all of the parts a thorough cleaning. That included the carrying case, which went from being covered in mold to a brilliant white as pure as the driven snow. Then they took apart the TV, and kept just the LCD panel. As luck would have it, the new panel fit perfectly into the space that the original LCD used to occupy inside of the PPC640 case. The PPC640 has an external monitor output, so Drygol soldered a D-sub cable to the LCD’s control board.

The problem, however, is that the Amstrad PPC640 external monitor output only supports CGA/MDA video and not the output used in modern (ish) monitors and the D-sub connection Drygol planned to use. The solution came in the form of a converter designed for Tandy/Radio Shack TRS-80 Color Computer models. That was mounted inside of the PPC640, and the new LCD was working properly after some tweaks to the DIP switches that control the external video output. As a bonus, full-color video is supported on external monitors, meaning this Amstrad PPC640 now has a color monitor!