The next consideration was what CAD software to use for this endeavor. It so happened that there's an old copy of Visio Technical 4.5 lying around, so I installed and fired it up to do some fiddling around. It made an instant connection that persuaded me this was the best tool for the job! The first thing I did was produce a mechanical drawing of the front panel, as shown below, which took me just slightly over half an hour. Not bad for a start, eh?
The rear view of the unit was more complicated with the CPU board and the display driver sub-assembly visibly in view, but I managed to draw that too though at a much later date when I had the time to do so. However, I will not be showing it here since that is not the main focus of the story. Still, I'm sure you'll agree that Visio fared pretty well for illustration purposes (and we're just warming up!).
After disassembling the unit, I proceeded to analyze the infrared matrix sub-assembly and gathered whatever information I could find on its components. What intrigued me was the primitive yet beautiful design of this multi-layered PCB—the making use of narrow-angled beam infrared emitter and sensor diode pairs—to achieve the X and Y coordinates mapping for the touchscreen effect that was the usual practice back in the mid-1990 era. It had many of the elements that made reverse engineering particularly interesting and challenging, such as the peculiar shape and size of the PCB, the presence of through-hole and surface-mount components that are mounted on both sides, and the thick conformal coating. That's quite a handful for my virgin attempt but I went ahead anyway.
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