"Serial IO board K1 is controlled by "SBYB" which traces to signal "BYPRLY". The names suggest "bypass relay" but under what circumstances is this signal set/cleared? In other words, when does K1 open the data out line?"
Well I found the answer thanks to another KPA500 owner running a similar test. It turns out that setting SER POLL to OFF and remaining in the Menu stops polling but leaves the relay closed with -12 V on pin 3. Only when the menu is exited does the relay get deactivated and pin 3 goes open circuit. Similarly, opening the menu and setting SER POLL from Off to On leaves the relay open and the relay only closes when the menu is exited. I wonder how many KPA500 owners have been caught by this. 73, Andy k3wyc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
