My K3 into the KPA500 for over ten years . . . . The FAN REV is 1.54 (this might be software) The resting temp is 27C. When on RTTY I set the FAN to 4. Otherwise 2 for most of the time. Knowing temperature is the killer of electronics (short of lightning) I try to keep things cool. For 10 years I have had a 24 V muffin fan running at 12 V sitting on top of the amp (and another one on the K3).
To rule out VSWR issues, how about connecting the KPA500 directly into a dummy load. Pete W4WWQ On Sun, May 14, 2023 at 1:24 PM James Bennett via Elecraft < elecraft@mailman.qth.net> wrote: > Got a question (problem?) regarding the fan in my KPA500. I'm driving the > amp at 29 watts from a Kenwood TS-890S. The amp is connected to a KAT500, > which in turn is hooked to a 30 foot tall Zerofive flagpole vertical. The > tuner has provided me with a nice 1.2:1 SWR, as displayed on the amp. The > resting temp of the amp shows 42C. At 29 watts input to the amp, I’m seeing > about 480 watts of power from the amp. The amp has nothing sitting on top > of it, and the wall behind it is over 12” away. There is about 2” clearance > on either side of the amp, and it is sitting on top of the KAT500. > > The issue: The fan comes on in a very short time - less than 20 seconds - > and the temp display runs up to 50+ degrees. If I start calling CQ or get > into a QSO, it doesn’t take long for the temp to show over 60 degrees and > the fan is running at max. > > When I had a K3 and more recently, a K4D - this did NOT happen. The fan > would come on but NEVER at the max, loud level. Interestingly, many moons > ago I also had a KX3 and had it connected to the KPA500. I noticed that the > fan would also come on fairly quickly with that rig driving the amp, but I > never thought too much about it. Until now... > > But now, I think there is some sort of problem. It seems to me that the > temp shouldn’t get that high that fast nor should the fan start roaring in > that short amount of time. I could understand it if the SWR was really bad, > but at 1.2:1???? > > Any ideas why the amp fan should be acting this way with a non-K3 or > non-K4 driving it? > > Jim / K7TXA > ______________________________________________________________ > 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 plasc...@gmail.com -- Pete Lascell Forest, VA ______________________________________________________________ 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
