David, Actually the 'where to start' question does not have a good answer from your description. The problem characteristics have to be better defined before plunging in and actually doing anything physical to the K2 (i.e. you don't want to 'fix' things that are not broken).
Since you get a change in the howl pitch when touching R24 and R25, it would be wise to first verify the PLL/VCO signal. If you have a general coverage receiver, tune it around the 20 meter VFO frequency (about Dial frequency plus 4915 kHz - or 18915 when tuned to 14000) and observe what the VCO signal sounds like. If you cannot obtain a strong enough signal, by dropping an antenna wire to the GC rcvr into the K2, you stick a wire into TP1 to serve as a short antenna. Everyone has a differnt definition for 'howl' in their minds, so if you can be a bit more descriptive about the sound it may be helpful. Is it only receive, or is it present in the transmitted signal? How loud is it? Could it possibly be a noise originating outside the K2? Do you hear it with the antenna disconnected? Tell us what tools you have available there - frequency counter, 'oscilliscope, etc. 73, Don W3FPR > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of David C Dawson > Sent: Friday, January 12, 2007 2:26 AM > To: [email protected] > Subject: [Elecraft] K2 #05386 has developed a problem > > > Hi, > My K2, recently completed, has developed a 'howl' on the 14MHz band. > > I had finished the rig and got it tweaked and performing very well, > even making a contact with K6STA on 20 meters (He gave me 579) > > I then constructed the KIO2 and got it working with my logging program > (tlf). > > The KIO2 began to malfunction, so I took it out and re-did the wiring on > the aux board. > > I replaced it and it seemed to be fine except for a brief glitch. > > Then I noticed that there was a 'howl' all across the 14MHz band, but > not on any other band. > > I removed the KIO2 and set up the rig. The howl was still there, exactly > as before. > > What could have happened? > > I noticed that touching the leads of R24 or R25 modified the noise, but > that's about what I know. > > The noise covers the whole band as far as I tuned. > > Anybody got a suggestion for how I should start troubleshooting? > Thanks > -- > David Dawson > > People of privilege will always risk their complete destruction > rather than surrender any material part of their advantage. > -- John Kenneth Galbraith > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > 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 > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.432 / Virus Database: 268.16.9/622 - Release Date: > 1/10/2007 2:52 PM > -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.16.9/622 - Release Date: 1/10/2007 2:52 PM _______________________________________________ Elecraft mailing list Post to: [email protected] 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
