This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
Supposedly, the purpose of having the Focus spin down and stop after 2, 10, or whatever minutes of idleness is to prevent over-heating and unnecessary wear. After a few days of trying various TO settings, I set my "Time Out" to "Never" and have had no problems with over-heating or crashes even after many all-day sessions. By: Rubywand
 
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