In my last three posts, I prototyped getting an HD9800 video conversion board to accept signals from my old computers and display them reasonably satisfactorily on an LCD VGA monitor.

But there is one major difference between the original video and the VGA signal: scanlines.

After my testing of the HD9800 video converter board, I wanted to experiment with reprogramming the TV5725 video conversion chip on the board.

A number of people have already done sterling work on reverse engineering it to invoke modes not supported by the supplied on-screen controller.

I hope to build on their work :-)

After my initial research and designs, I started ordering components for the video converter part of my RetroMatic 2000.

It’s based around a GBS8200 board (or the HD9800 clone version), with extra circuits to modify the input (clean up the sync signal) and output (generate scanlines).

Here’s a scrapbook from my prototyping phase…

I’m building what I call the “RetroMatic 2000” for the Retro Challenge 2017/04.

I’ve been planning, designing, and prototyping it for the last month or so.

Here’s a scrapbook of what I compiled during the research and development phase for the video converter aspect of the project (converting 288p RGB or mono composite from a retro computer to VGA suitable for an LCD monitor).

Today is the first day of the Retro Challenge – a one month semi-formal excuse to do something cool with retro computer technology throughout April.

I only found out about this a couple of weeks ago. I’ve just spent March planning and prototyping a retro computing project, but I haven’t started the main build yet. I’d also been vaguely thinking about publishing my progress somewhere so others could appreciate what I’m doing. So this seemed the perfect excuse!