Tempest wrote:
It's the plastic. Some batches of plastic turn yellow when they start to break down (usually because of UV exposure, but not always). You see this alot with game systems (SNES mostly) and keyboards. The general rule of thumb is that if it hasn't turned yellow yet, then it probably won't.
I've seen several systems that had clear "prints" of the drives or monitor that sat atop them for a long time, with regular exposure to UV either from flourescents or from daylight. This is clear evidence that most yellowing is a result of exposure to light. Note that many systems are much yellower on the top and one or two sides, but not on the other sides--away from the windows. If you find one that has not yellowed, it just hasn't yet been exposed to enough UV. -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."