Thanks Joe - you picked it in one! No voltage on PTT IN. RFC1 on the RF board has failed open (9 M Ohm on my meter) and bypassing it restores the PTT IN 5V line voltage and function, as you'd expect.
It's a surface mount component on the bottom of the RF board, for those who might need to know in the future. Next challenge is to replace it - I'm not very experience with SMC building, but I'll give it a go. Or, would there be any problem replacing it with a standard RFC of the same value if I can configure it to fit? 73, John VK7B -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-PTT-IN-problem-cont-d-tp7457978p7459233.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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html

