Mike, thanks for taking the time to respond. I have done lots more tests and narrowed things down.
First off, the K2 is on the bench with a dummy load and power turned down to as low as it will go, so RF is not a problem. The /DASH line on pin 29 of the MCU is "floating" around 2 volts. I am guessing it should be 5 volts like the /DOT-PTT without keying it. That is what the voltage chart says. Behavior is erratic. Sometimes when I turn it on it starts keying right away. Or when I touch the paddle. Same thing with a straight key in "hand" mode. And when it gets in this state the menu button doesn't work, even if it is not keying. All the other buttons seem fine. I have a scope, so I looked at the /Bank1 and /Bank2 signals - all looks OK. I checked the 82k resistor network for the /DOT-PTT and /DASH with an ohmmeter - they look fine. 5 volts is there and good. ~80k to 5 volts on both signals. But the dash is not pulling all the way up. It is erratic - sometimes I can get it back to normal by pulling out the key plug and so forth. But not often. I removed the bottom panel with the heatsink screws (what a pain) and reheated the key connector and looked at everything down there and traced the dot/dash signals back - all looks fine. So no obvious solution. I needed to upgrade the MCU firmware anyway, so I ordered one. It will be few days before I get that, but if you have another suggestion I would appreciate it. Thanks, Sam N4MAP On Sunday, May 31st, 2026 at 8:14 AM, Michael Carter via Elecraft <[email protected]> wrote: > Hi Sam, > > You identified two issues with your recently acquired K2: rig locked into > transmit mode after using a straight key, and lack of response to MENU button > presses. It's not immediately apparent to me that these issues are connected > causally, i.e. that the MENU button malfunction was caused by the event that > caused the rig to lock up in transmit mode. > > Had you been using a straight key for some time prior to the transmit lockup? > You mention alternating between straight key and paddle. How do you have > the KEY input wiring configured to share the KEY input between the straight > key and the paddle? > > As with all of the front panel buttons, the MENU button serves two functions: > a short press opens the MENU options, a long press opens the EDIT function. > From your report, there are no MENU options visible on the display with a > short press of that button? > > The K2 control design strobes each of the buttons sequentially and looks for > switch closure. The MENU button is strobed upon activation of the /BANK1 > signal (logic low) AND sampling of the D7 input to the parallel-to-serial > converter. D7 is also used for the XIT/PF2 button sensing when the > /BANK2 signal is asserted. Please check that the XIT button is responsive to > both short and long presses. If so, that suggests that the MENU button has a > mechanical failure or there may be a weak solder joint under it that has > opened under repeated button presses. > > I'll give some more thought to the transmit lockup issue later today. I've > not experienced that kind of lockup with my K2 except when there was > excessive RF induced on the external wiring due to common-mode currents in > the antenna connection. > > 73, > Mike, K8CN > ______________________________________________________________ > 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] > ______________________________________________________________ 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]
