[Elecraft] K2 resets in operation or TUNE selection - continuing problem
This is an issue I have been dealing with for some time now and the troubleshooting process has been complex so I will try to be specific about my questions. Bear with me as I summarize the issue. My K2/KPA100 performs a complete power reset when TUNE has been activated for about 10 seconds. It indicates Hi Cur at that point. The radio has to be on for approximately 2 hours before it exhibits this behavior. This problem originally occurred in 2015. Don Wilhelm helped me troubleshoot it and I thought a solution had been found. The problem showed up again in 2018 and Don worked with me extensively to attempt to resolve it to no avail. Don finally threw in the towel on email troubleshooting and suggested I try replacing components in suspect circuits which I have done. Note that I have probably put in 100+ hours on this effort. We narrowed the problem down to something in the SWR Bridge or the LPF since it appears that the K2 is calling for more power than it can deliver increasing the current until it resets. With that very brief summary in place I will now ask some specific questions which I hope will be picked up on by someone at Elecraft. NOTE: DURING ALL THE TESTING THE KPA100 IS CONNECTED BUT WITH POWER SUPPLIED THROUGH THE BASE K2 CONNECTOR. I have measured the increase in current in TUNE when the Hi Cur event has occurred. I broke the 12V supply circuit to the base K2 PA and associated components to measure the current. During normal TUNE the current is 660mA. During the Hi Cur event the current is 1.9A - an increase of 1.2A. The current shown on the K2 display is 4A total. 1. What is the actual reset mechanism? I thought the re-settable fuse would not trip until 5A was drawn. If it is re-setting, why at 4A? 2. Why is there a 10 sec delay from initiation of TUNE until the K2 resets? 3. Is there some other mechanism for reset (in the firmware?) in the K2? 4. I have replaced every active component in the SWR Bridge including twice replacing the D16 & D17 diodes. I have removed and examined T4. What other components should I look at replacing? This is assuming, of course, that the problem is in the Bridge. 5. Is there something else that needs to be examined? Although I can't imagine what hasn't been examined during the troubleshooting by Don and myself. 6. A basic question - why is there a 2 hour period of power on before TUNE causes a reset? Believe me I have examined this one over and over. I don't expect an answer - just wanted to throw it out there. NOTE: I HAVE PERFORMED ALL UPGRADES DURING THIS ENTIRE PROCESS INCLUDING THE BASE PA UPGRADE. NOTE: IF ANYONE WANTS TO TAKE THE TIME TO READ IT, I HAVE COMPILED AND EDITED ALL OF OUR EMAILS INTO A MORE READABLE DOCUMENT. I REFUSE TO LET THIS THING BEAT ME! THERE HAS TO BE A SOLUTION TO THIS! Thanks for reading. 73, Jim WA4YWM -- Sent from: http://elecraft.365791.n2.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
[Elecraft] K2 w/KPA100 power resets after approximately 2 hrs of turn-on time
I originally posted this in July and I still have the problem. The issue is as described below past the dashed line. Note that the issue happens even if I haven't been transmitting. Don Wilhelm helped me attempt to troubleshoot the issue. We eliminated the base K2 as the source. After that, at Don's suggestion, I installed the KPA100 upgrade kit - no success. At this point we gave up. Recently I replaced D16 & D17 on the KPA100 after reading about similar problems caused by the damaged diodes. Still no luck. Has anyone out there had a similar issue? 73, Jim Elmore WA4YWM -- I have a K2 serial no. 4729 with the 100W amp which I have been using for almost 10 years. It recently developed a problem with the following 2 symptoms: 1. After operating for some time (perhaps 1-2 hours) the Tune function will begin to display 1 W with a 1.0-1 SWR on all bands. It normally displays 22-23W with the correct SWR shown. 2. At the same time, if I attempt to transmit, the K2 will apparently begin to draw too much current and it shuts down and re-starts. The Tune function also shuts the K2 down at this point. I observed the same behavior on a dummy load - to eliminate an antenna or feedline issue. I also left the power supply on while letting the K2 cool down to see if the supply was the source of the problem. Apparently not since the K2 would operate for a significant time after turning the K2 back on. -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-w-KPA100-power-resets-after-approximately-2-hrs-of-turn-on-time-tp7610298.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
[Elecraft] K2 w/100W amp has temperature related xmit shutdown
I have a K2 serial no. 4729 with the 100W amp which I have been using for almost 10 years. It recently developed a problem with the following 2 symptoms: 1. After operating for some time (perhaps 1-2 hours) the Tune function will begin to display 1 W with a 1.0-1 SWR on all bands. It normally displays 22-23W with the correct SWR shown. 2. At the same time, if I attempt to transmit, the K2 will apparently begin to draw too much current and it shuts down and re-starts. The Tune function also shuts the K2 down at this point. I observed the same behavior on a dummy load - to eliminate an antenna or feedline issue. I also left the power supply on while letting the K2 cool down to see if it was the source of the problem. Apparently not since the K2 would operate for a significant time after turning it back on. I have not tried any other troubleshooting. I thought I would see if anyone could point me in the right direction before I took the shotgun approach. TNX for any help & 73, Jim WA4YWM -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-w-100W-amp-has-temperature-related-xmit-shutdown-tp7604669.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
