I know I have. Late at night, I often look at the shelf my old Super Nintendo sits on and ask myself "Why the hell did the bottom of my SNES turn yellow but not the top - WTF is up with that?" - Yeah, I know, I have too much time on my hands. Anyway, the good folks over at Vintage Computing and Gaming have finally provided the answer - and maybe now I'll be able to get some much needed sleep.
Anyway, the answer is a little complicated, so I'll simplify things and let those of you looking for a more in depth answer to click the link and read the whole article - something I highly recommend as it's not just an interesting topic, but something that could be of great help to console collectors everywhere. In short, the problem lies with the manufacturing process used to make certain plastics, including ABS plastic, which is what the Super Nintendo is made out of.
In the case of the SNES, it would at least appear that in older models too much of a flame retardant chemical was used in the mix, and that causes the plastic to degrade over time - and that degradation is accelerated when the console is exposed to certain conditions. As for cases like my trusty old SNES and it's color issues, it would appear that it was built some time during the period in which those ratios were corrected. In other words, the bottom half of the case was made before the correction, the top half afterwards.
This isn't something that only affects the Super Nintendo though. I'm sure everyone has seen an old computer monitor, computer or the like that has yellowed over time. That's not dirt, folks(well, at least not all of it is) - it's the same degradation process. That said, Vintage Computing and Gaming had some advice on ways to at least slow the degradation process;
- Keep your most prized collector pieces out of rooms with fluorescent lighting.
- Keep your units away from windows and sunlight because, like the fluorescent lighting, the UV exposure will drastically hasten their discoloration. Even indirect sunlight can do damage over time.
- Avoid placing your unit next to a heat source such as a radiator, air duct, or fireplace. Or in the fire.
- Do not keep your machines in a room where people smoke tobacco (wacky or otherwise).
- Apply a coat of UV protectant.
- Try not to breathe too heavily upon your console’s exterior. Ok — this one’s a joke.
- For the ultimate in protection, seal your unit in a lead-lined, temperature-controlled, evacuated vault away from any radiation, visible or otherwise. But hey, what fun is that?" - Vintage Computing and Gaming
Like I said, the article is a must read for anyone who's ever wondered why that yellowing occurs and what they can do about it - check it out at this link.