"Any or all of the above" - several people have suggested good ideas. The strongest possibilities are a loose TMP connector or a multi-way connector that needs re-seating. Since the faulty connection is "right on the edge" between working and not working, even a very gentle tug on a TMP connector or a gentle jiggle of a board should reveal the problem.
The best tool that I have found for inserting, checking and removing the TMP connectors is a pair of artery forceps. The finger loops and the click lock give far better control than long-nosed pliers (smart people, those surgeons!). Forceps are available in several different sizes and shapes, and probably the best choice for working inside the K3 is the straight 6-7in pattern. They are cheap and easy to find on eBay, and well worth trying. Since Chris is in the UK, a good alternative to Deoxit for treatment of connector pins is Contralube 770 which is available from Maplin. Regarding the rear-panel SO239, I was the person who suggested making a direct ground return between the connector flange and the KANT3 or KAT3 board. OK, so "it works already" and "7999 other K3s can't be wrong"... but it still isn't good practice to make a single-wire link to the center pin while leaving the equal and opposite return current to find its own way back to the board through a single-point connection between the rear panel followed by a long, thin support pillar. The new connection is made by attaching a solder tag under the 4-40 screw (as seen in the Assembly Manual, Figure 29) and another tag to the nearest point on the flange of the SO239. No wire is needed; the two tags are simply bent until they overlap, and then soldered to make a shortest possible return connection. Ohm's law dictates that this will now be the preferred return path, so the poorer path through the metalwork is the one that becomes redundant. 73 from Ian GM3SEK >-----Original Message----- >From: Elecraft [mailto:[email protected]] On Behalf Of >Jim LeFevre >Sent: 21 April 2014 21:03 >To: [email protected] >Subject: Re: [Elecraft] K3 intermittent receive issue > >I recently corrected a similar problem on the K3 I put together. Same >symptoms, and I found when moving the coaxial cable on the main antenna >on the outside of the radio, I could duplicate the problem. I replaced my >exterior rg-58 cable/connector three times without relief, then found that >the SO-259 on the radio was the problem as it makes its shield connection >by mechanical contact with the case. Cleaned all, tightened, all works good >now. I think someone had posted that they made a redundant jumper to tie >the connector to the antenna shield by way of one of the connector nuts to >prevent this problem. Good luck. Jim WN8A >______________________________________________________________ >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]
