[Amps] Fan control

[Gary Smith]

Bill,

I have the temp probe for the electronic Sunbeam cooking thermometer 
in the amp's airflow and it does a really nice job of displaying 
current temps. I have it set so if the temp of the exhaust goes over 
150, it beeps just like the Turkey is done. It would be ideal if 
there were a usable output from it to trigger a SS relay to switch 
wipers on the wire resistor to change fan speed as the thermometer is 
sitting on top of the amp & piggyback rather than internal works fine 
for this.

I think the only thing I don't like about the piggyback/external 
thermostat approach is Murphy's Law of something getting dislodged, 
internally mounted, that wouldn't happen.

73,

Gary
KA1J


> ------------ ORIGINAL MESSAGE ------------(may be snipped)
> 
> On Wed, 14 Sep 2016 21:38:54 +0100, Ian wrote:
> 
> >One of the boards is used
> >inside a transceiver 
> 
> REPLY:
> 
> Inside a transceiver is one thing, inside a high power amp is
> something else. I'd suggest mounting it outside the cabinet, directly
> in the exhaust air stream. Even then check carefully for RFI to the
> unit affecting the speed and RFI from the unit heard in the receiver. 
> 
> These units almost certainly apply DC to the thermistor, so if
> necessary you can mount the thermistor (heavily capacitor bypassed) in
> the air stream and the rest of the unit in a shielded box somewhere
> else. 
> 
> Great suggestion Ian, thanks!
> 
> 73, Bill W6WRT