**Hobbyist Builds HDMI ISA Graphics Card For Vintage PCs By Improving Graphics Gremlin**

Earlier this year, Singapore-based embedded security researcher yeokm1 built a ChatGPT client for MS-DOS.
Now they're back with a new project:
HDMI is a relatively modern video connector we take for granted on modern PCs and monitors. Now vintage PCs can join in the fun too with a native connection to modern HDMI monitors without any additional adapter.

Two years ago, I learned of an open-source project called Graphics Gremlin by Eric Schlaepfer who runs the website Tubetime.us. It is an 8-bit ISA graphics card that supports display standards like Color Graphics Adapter (CGA) and Monochrome Display Adapter (MDA). CGA and MDA are display standards used by older IBM(-compatible) PCs in the 1980s. The frequencies and connectors used by CGA and MDA are no longer supported by modern monitors hence it is difficult for older PCs of the 1980s era to have modern displays connected to them without external adapters. Graphics Gremline addresses this problem by using techniques like scan doubling (for CGA) and increasing the vertical refresh rate (for MDA) then outputing to a relatively newer but still old VGA port.

I fabricated and assembled the design then installed it into my IBM5155... I decided to modify the Graphics Gremlin design so it can connect natively to an external HDMI monitor and service the internal Composite-based CRT at the same time.

The post concludes triumphantly with a photo of their IBM 5155 running the CGA Compatibility Tester displaying the color palette.

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 Wow, it seems like the retro tech enthusiasts are really going all out to bring vintage PCs into the modern era! I mean, who needs those clunky old connectors when you can have fancy HDMI? It's like giving a typewriter Bluetooth capabilities—why not?

Kudos to yeokm1 for taking on the challenge and improving upon Eric Schlaepfer's Graphics Gremlin. Now, not only can these vintage PCs support display standards from decades ago, but they can also effortlessly connect to modern HDMI monitors. It's like time travel for your computer!

I must say, seeing that IBM 5155 running the CGA Compatibility Tester with a vibrant color palette is quite impressive. Who says retro can't be stylish? Just imagine playing some classic games or coding in style on that beautiful old-school machine.

So rejoice, my fellow tech aficionados! Thanks to innovative minds and tinkering skills, vintage PCs now have a ticket to join in the fun of modern displays without needing any additional adapters. Hats off to yeokm1 for bridging the generation gap between technology eras—it's truly an achievement worth celebrating!

Now excuse me while I go dust off my Commodore 64 and dream of HDMI glory...