I guess it is pretty old, SN 2060 Rev A board KSB2 104 K2IOC 102 K2MCU 201F ATU Rev C KIO2 Rev B NB 102 KAF2
A jumper and a cap have been added to the back of the control board. No luck so far finding a leak to ground - will keep looking... Sam On Sunday, May 31st, 2026 at 4:26 PM, W3FPR <[email protected]> wrote: > Sam, > > What is the firmware level in that K2, and what is the serial number? > Does it have either the KIO2 or KPA100 installed? > Those may sound like questions that are not relevant, but if the > firmware is downlevel and the SN is below 3000, you may have to make > some changes to the control board (not difficult) when you upgrade the > firmware. > Those are the same changes that must be added when the KIO2 or KPA100 is > added to a level A K2. It is just 1 cut, and one wire add along with a > .001 uF capacitor. > > 73, > Don W3FPR > > On 5/31/2026 10:33 AM, Sam Smith via Elecraft wrote: > > 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] > > ______________________________________________________________ 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]
