I've got this same problem myself and I found this, I haven't put one together yet, but it looks promising:<br><br><a href="http://www.heatsink-guide.com/content.php?content=control.shtml">http://www.heatsink-guide.com/content.php?content=control.shtml</a><br>
<br>73<br>Stephen<br>K1LNX<br><br><br><div class="gmail_quote">On Thu, Apr 2, 2009 at 2:17 PM, John Scoggin <span dir="ltr"><<a href="mailto:aat3bf@armymars.net">aat3bf@armymars.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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<p><font size="2" face="Courier New"><span style="font-size: 10pt;">All --</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p style="text-align: left;" align="left"><font size="2" face="Courier New"><span style="font-size: 10pt;">You might find this page
useful: <a href="http://www.irlpcables.com/alinco_drxx5t_mobile.html" target="_blank">http://www.irlpcables.com/alinco_drxx5t_mobile.html</a></span></font></p>
<p style="text-align: left;" align="left"><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">I agree with Randy – when it comes to “cooking my finals”,
I prefer a simple solution. If you really want to do it right, use a
normally-open thermostat to control the fan power and a normally-closed
thermostat to control the transmitter main power. </span></font><font face="Wingdings"><span style="font-family: Wingdings;">J</span></font> (obviously
with values of operation far enough apart NOT to fall into each other’s
dead-band!)</p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">73,</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">john</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">____________________________________________</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">John K Scoggin, Jr. W3JKS/AAT3BF/AAM3EDE/AAA9SL</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">"WLMM - Sic faciunt omnes (Winlink 2000, Everyone is doing
it.)" </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">US Army Military Affiliate Radio System </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Delaware Gateway Station AAB3DE</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Special Consultant - Technology</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Emergency Operations Officer - Delaware</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">ARRL Assistant Section Manager - Delaware</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Email: <a href="mailto:aat3bf@armymars.net" target="_blank">aat3bf@armymars.net</a></span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Telephone: (302) 451-5000</span></font></p><div><div></div><div class="h5">
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p style="text-align: left;" align="left"><font size="2" face="Courier New"><span style="font-size: 10pt;">-----Original Message-----<br>
From: <a href="mailto:app_rpt-users-bounces@qrvc.com" target="_blank">app_rpt-users-bounces@qrvc.com</a> [mailto:<a href="mailto:app_rpt-users-bounces@qrvc.com" target="_blank">app_rpt-users-bounces@qrvc.com</a>] On
Behalf Of Randy Hammock<br>
Sent: Thursday, April 02, 2009 1:41 PM<br>
To: <a href="mailto:app_rpt-users@qrvc.com" target="_blank">app_rpt-users@qrvc.com</a><br>
Subject: Re: [App_rpt-users] URI's I/O fan control</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">On Apr 1, 2009, at 6:33 PM, Will Wright wrote:</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> Hello to the group,</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">></span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> I wonder if anyone would like to share a timing circuit and it's</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> programming use with one of the URI I/O pins, lets say to control
a </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> fan</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> to keep the transmitter cool on transmit and off when not in
transmit.</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">> Thanks</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">I prefer mounting a thermal switch on the heat sink of the </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">transmitter. This way, the fan is controlled by real need, not
some </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">imagined arbitrary need. When the ambient temp is cool, the fan
runs </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">very little. When the ambient temp is elevated, the fan runs
longer. </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">But the transmitter stays a comfortable temp.</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">--</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">Randy Hammock KC6HUR</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"><a href="http://kc6hur.net/%7Erhammock/" target="_blank">http://kc6hur.net/~rhammock/</a></span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"><a href="http://irlp.kc6hur.net/" target="_blank">http://irlp.kc6hur.net/</a></span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">If there are no horses in heaven, then when I die, I want to go
where </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">they went.</span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;"> </span></font></p>
<p><font size="2" face="Courier New"><span style="font-size: 10pt;">_______________________________________________</span></font></p>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Stephen Brown - ARS K1LNX<br>Johnson City, TN EM86<br><a href="http://www.k1lnx.net">http://www.k1lnx.net</a><br>