Hi Mark I can relate to what you are experiencing with the KPA500.
You do not mention which rig you are using to drive the KPA500 or how you have the transmit switching configured. I bought a new TS590SG some months ago and set it up using the solid state switching which on the face of it is exactly the same as the TS990 which works perfectly with the KPA500. However, with the TS590SG, all it did was exactly as you describe. What is happening is that the transmit switching arrangement - whatever it is that you are using - puts the KPA500 permanently in a transmit state and then it works normally to amplify the signal when you key the rig (or horror of horrors speak into the microphone. If by any chance you are using a TS590SG you can test the amplifier for correct operation by changing to the relay switching rather than solid state. In my case, the matter was resolved after some liaison between the Australian Kenwood Service Centre and Elecraft determined that the pull up or pull down resistor ( I can't remember which it was) in the TS590SG was too low such that it put the KPA500 permanently in a transmit state. Kenwood simply increased the resistor appropriately and now it works fine just like the TS990. I hope that might point you in the right direction. 73 Barry VK2BJ On 16 November 2015 at 07:24, Mark Goldberg <marklgoldb...@gmail.com> wrote: > I will contact Elecraft tomorrow, but posting in case someone > recognizes the symptoms. > > I just put together a new KPA500 kit. When I select Operate, the RX > through the amplifier is significantly attenuated, many 10s of dBs. > The amp will also amplify even with nothing connected to the PA Key > RCA jack. It seems to amplify OK, 35W in gives 400W out. In Standby > the RX and TX pass through the amp as expected. > > It seems to me that it thinks PA Key is enabled all of the time, so > when I switch to operate it is in TX mode immediately. I do not see a > short at the RCA jack. > > Any idea of what is going on? > > Mark > W7MLG > ______________________________________________________________ > 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 vk...@optusnet.com.au > ______________________________________________________________ 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
