Hi Barry, While your experience suggests that a transistor switch will probably save the day I also wonder if the problem is the result of the absence or presence of a pull-up resistor or perhaps a floating common connection between the rig and amp. Maybe a resistor in the plug would help. I suppose there is some way to check this out.
73, Mike K2MK Barry Simpson wrote > .............partial quote from Barry.............. > The conclusion is therefore that from an initial OK position in Stby and > Oper as soon as the first character is keyed, the solid state switch in > the > TS590SG "hangs" resulting in the KPA500 being permanently in the transmit > state. The situation only clears when rig and amp are turned off, the Din > plug is removed from the TS590SG and reinserted and both are turned back > on. I can then switch the amp back to Oper and all is fine until the very > first morse character when it all happens again. So as it stands, there > appears to be incompatibility between the TS590SG solid state amp switch > and KPA500. > > As an interim measure, I have rewired the Din plug to use the noisy relay > for the amp control and that works fine. The TS590SG does output 12V to > the > solid state switching pin in certain configurations as did the TS590S. I > had a TS590S and I wired a single transistor solid state switch inside the > Din plug and that worked perfectly so I am going to do the same again, > which should solve the issue. Unfortunately, I gave away the TS590S cable > I > had made up to the guy I sold the TS590S to. I never got the very bad > spike > issue fixed but the buyer did not mind as he doesn't use a linear. > > It really is a pity as I thought that the new linear switching circuitry > in > the TS590SG was a real step forward but it is not to be, at least not with > the KPA500. > > 73 > Barry VK2BJ -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-Issue-tp7597707p7597728.html Sent from the Elecraft mailing list archive at Nabble.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
