Actually, that’s 63 C at the PA device location on the PC board. The outside surface of the heat sink itself is quite a bit lower in temperature.
Wayne N6KR > On Aug 6, 2017, at 11:39 AM, Wayne Burdick <n...@elecraft.com> wrote: > > The KX3 and KX2 max heat sink temperature is 63 C. At that point power is > automatically dropped to 5 W. If it reaches the max temp again, transmit is > exited. > > Wayne > N6KR > > > >> On Aug 6, 2017, at 10:27 AM, Jim Brown <j...@audiosystemsgroup.com> wrote: >> >> A well designed output stage SHOULD be hot to the touch. The temperature >> component of protection in Elecraft output stages seems to kick in when the >> internal temperature approaches 70 deg C. You can see this, for example, by >> watching temperature in the KPA500 and listening to fan speed. The function >> of the heat sink is to act as a conductor between the semiconductor >> junctions and the surrounding environment, and increased mass acts as a sort >> of buffer. >> >> 73, Jim K9YC >> >> On 8/5/2017 2:53 PM, Jan wrote: >>> ""I've been doing a lot of FT-8 using my KX3 and my KXPA100 at 20 watts, >>> and have noticed that the KX3 is heating up quite a bit and is almost >>> hot to the touch"" >>> >>> Why should the KX3 be heating up, when the AMP is running only 20W ? >>> Is the KX3 "drive" not backed-down at this level ?? HELP >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to n...@elecraft.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
