Around here it seems pretty popular to be adding RGB signals to old consoles, dealing with suspect quality third party cables, converting old consoles to VGA or abusing VGA to display things with adapters, and timings is a concept pondered by many as well ( http://www.coranac.com/tonc/text/video.htm being a nice overview of GBA timings as it pertains to on screen stuff). I am also hoping in the future that we see replica or even more modern video cards made for older devices similar to how we are seeing replica sound cards and chips for them made today (see some of the modern sound blaster clones for this one, though for the token link I put here I will instead go with http://macgateway.com/featured-articles/sound-card-history/ ), and are also seeing FPGAs twisted into replicating complex old school hardware ( https://gbatemp.net/threads/the-upc...nboard-megacd-recreation.542791/#post-8705929 ).
The video at the top covers someone building up a VGA signal from basic components, but in a nice visual way with good editing. Those looking for ultra simplicity might have to rewatch a section or two when he covers some simplifications done to allow it to work with common chips, however at the same time that is also a superb primer on practical electronics design and simplification.
Even if you only end up soldering something to your old school device/making up a cable from a diagram I find it still helps to have some idea about what is actually going on.
