[Elecraft] 20 meter problem on new K2
I just noticed that my K2 build 43xx is almost totally dead on 20 meters. I think all the other bands are OK. I hooked up my N-Gen and could not hear anything on 20. I thought I could use a scope to follow the generators noise signal but the scope makes about as much noise as the generator when going through the bandpass circuit. I am guessing it is probably bandpass or low pass and I need to start checking to make sure the relays are making contact, etc.?? It worked when I built it a couple months ago and am not sure when it quit as I dont use 20 often. This K2 is totally optioned and I have removed the 100 watt PA to make sure it is not the culprit. Any comments on the best way to trouble shoot this? Thanks and 73, Rich kd0zv ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] 20 meter problem on new K2
I would forget checking relays for the moment. Take a look at the coupling capacitors for the 20m/30m circuit, the ones installed on the bottom of the board. Make sure solder flowed through to the top of the board for good connection to the traces up there. This was my 20m problem. 73, Joe, aa4nn I just noticed that my K2 build 43xx is almost totally dead on 20 meters. I think all the other bands are OK. I hooked up my N-Gen and could not hear anything on 20. I thought I could use a scope to follow the generators noise signal but the scope makes about as much noise as the generator when going through the bandpass circuit. I am guessing it is probably bandpass or low pass and I need to start checking to make sure the relays are making contact, etc.?? It worked when I built it a couple months ago and am not sure when it quit as I dont use 20 often. This K2 is totally optioned and I have removed the 100 watt PA to make sure it is not the culprit. Any comments on the best way to trouble shoot this? Thanks and 73, Rich kd0zv ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] 20 meter problem on new K2
Thanks for the tips guys. After thinking about it, I am not 100% positive it worked when new. I do know it went through the alignment without problems, so I better check my wound coils just to be safe. Everything else seems to work OK and the only issue is lack of sensitivity on 20 meters. 73, Rich - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; elecraft@mailman.qth.net Sent: Saturday, October 30, 2004 7:16 PM Subject: Re: [Elecraft] 20 meter problem on new K2 A proper signal generator is just about essential to do the job. The problem is that you need a fair amount of signal to get any indication on the average oscilloscope. The normal method is to use an RF millvoltmeter to trace the path. You can use the Elecraft provided RF probe and a DVM providing you can inject an on frequency signal of sufficient level to work through the RX bandpass filters, etc. Elecraft give a figure of 140mV from the signal generator to carry out this test There is a good description how to go about it in the rev F, K2 manual Appendix E, Troubleshooting page 11. It is possible under extreme circumstances to use a TX into a dummy load as a signal source, but needs extreme care how you would extract sufficient level without smoking the RX front end. Much better to use a suitable signal generator. Bob, G3VVT ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] 20 meter problem on new K2
Did you seat the band pass filter trimmer caps, Rich? Many of those trimmer capacitors come from the factory needing to be twirled around a number of times to seat them so the sliding contact has electrical continuity. Just put your screwdriver in the slot and twirl it around a bunch of times, then re-try the alignment procedure. That CAN happen after the rig has been successfully aligned once. Apparently the contacts need a little 'exercising' to make them seat completely. Once that is done, they are fine. There's nothing wrong with the trimmers. That's the most common reason for a dead band, right up there with perhaps a dreaded PTTL (poorly-tinned-toroid-lead). Normally a PTTL won't make the rig quit though. It won't work from the first. If you didn't get ALL the enamel burned/scraped off of a toroid lead or you pulled the lead through the board passed the tinned segment so enamel-covered wire was in the hole, you might not be making electrical contact on that lead. Leads that aren't tinned properly look fine when soldered unless you look VERY closely at the wire. You'll often see a tiny ring of dark that looks like rosin around the conductor. It's actually the enamel. In that case the wire is trapped in the solder blob and won't pull out, but it isn't making electrical contact either. Ron AC7AC -Original Message- I just noticed that my K2 build 43xx is almost totally dead on 20 meters. I think all the other bands are OK. I hooked up my N-Gen and could not hear anything on 20. I thought I could use a scope to follow the generators noise signal but the scope makes about as much noise as the generator when going through the bandpass circuit. I am guessing it is probably bandpass or low pass and I need to start checking to make sure the relays are making contact, etc.?? It worked when I built it a couple months ago and am not sure when it quit as I dont use 20 often. This K2 is totally optioned and I have removed the 100 watt PA to make sure it is not the culprit. Any comments on the best way to trouble shoot this? Thanks and 73, Rich kd0zv ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] 20 meter problem on new K2
Yes, I remember reading about seating the caps. So I gave those two about 20 spins and did not help. The radio seems to peak OK going through the alignment. Just seems to have no sensitivity. I just pulled out a TenTec RX-320 and a S-9 singal on the TenTec is only a single bar on the K2. I have to crank the audio almost all the way up to listen as well. I doubt in my case it is tinning problems. I am prone to do stupid things but I am pretty good with solder and removing the enamel on the wire. NOT to say it isnt possible. I am surprised I did not notice this before but as I said, I am never on 20. Its a significant difference in audio as you switch to 20. Just to be safe I will check trace to trace on the circuit board to make sure the torroids are making good contact :) 73, Rich - Original Message - From: Ron D'Eau Claire [EMAIL PROTECTED] To: 'Rich McCabe' [EMAIL PROTECTED]; 'Elecraft Reflector' elecraft@mailman.qth.net Sent: Saturday, October 30, 2004 7:54 PM Subject: RE: [Elecraft] 20 meter problem on new K2 Did you seat the band pass filter trimmer caps, Rich? Many of those trimmer capacitors come from the factory needing to be twirled around a number of times to seat them so the sliding contact has electrical continuity. Just put your screwdriver in the slot and twirl it around a bunch of times, then re-try the alignment procedure. That CAN happen after the rig has been successfully aligned once. Apparently the contacts need a little 'exercising' to make them seat completely. Once that is done, they are fine. There's nothing wrong with the trimmers. That's the most common reason for a dead band, right up there with perhaps a dreaded PTTL (poorly-tinned-toroid-lead). Normally a PTTL won't make the rig quit though. It won't work from the first. If you didn't get ALL the enamel burned/scraped off of a toroid lead or you pulled the lead through the board passed the tinned segment so enamel-covered wire was in the hole, you might not be making electrical contact on that lead. Leads that aren't tinned properly look fine when soldered unless you look VERY closely at the wire. You'll often see a tiny ring of dark that looks like rosin around the conductor. It's actually the enamel. In that case the wire is trapped in the solder blob and won't pull out, but it isn't making electrical contact either. Ron AC7AC -Original Message- I just noticed that my K2 build 43xx is almost totally dead on 20 meters. I think all the other bands are OK. I hooked up my N-Gen and could not hear anything on 20. I thought I could use a scope to follow the generators noise signal but the scope makes about as much noise as the generator when going through the bandpass circuit. I am guessing it is probably bandpass or low pass and I need to start checking to make sure the relays are making contact, etc.?? It worked when I built it a couple months ago and am not sure when it quit as I dont use 20 often. This K2 is totally optioned and I have removed the 100 watt PA to make sure it is not the culprit. Any comments on the best way to trouble shoot this? Thanks and 73, Rich kd0zv ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
