The thermal switches sold for attic fans should work great. I bought one rated at 119ºF at a surplus store.
My S-COM controllers all had start-of-activity and end-of-activity macro triggers, which would be a more elegant way to do the timer-based function than a separate board with a 555 IC. Personal opinion, but I'd never put up a repeater that relied on a fan to keep temps within spec. I remember being horrified when Icom repeaters went to using a single internal fan with no air filter blowing through both the PA and power supply heatsinks, with the air exiting through a vent hole in the back. I much preferred the older style with the full-width cast-aluminum sink. 73, Paul, AE4KR ----- Original Message ----- From: Michael Ryan To: Repeater-Builder@yahoogroups.com Sent: Saturday, December 20, 2008 11:57 AM Subject: [Repeater-Builder] fan timer circuit I was directed by someone on the reflector here some months back, to a cooling fan timer circuit that is posted on the repeater builders website. I wonder if anyone has tried to build this ? - Thanks.. - Mike
