Hi Don, many thanks for your advice. Just opened up the K3, located Q3 and Q5 and measured there directly. Everything as it should be, 13 V bias to the gates during TX, Drain switching to ground, everything as expected. Uh? Same measurements at the RCA jack from the PCB and everything fine. Measured again from the outside and ... everything fine?! Connecting the cable, PA is switching. Closing the cover and putting on the screws and still everything fine?! I have no clue why it's working perfectly now and didn't before ... *scratching head*
Oh well, maybe my K3 simply wanted somebody to look into it's beautiful inards again. ;-)) Andyway, thanks again for your help. Must be magic emails in this case. ;-)) 73, Olli - DH8BQA ----- Original Message ----- From: "Don Wilhelm" <w3...@embarqmail.com> To: ""Oliver \"Olli\" Dröse"" <dro...@necg.de> Cc: <elecraft@mailman.qth.net> Sent: Sunday, October 10, 2010 6:32 PM Subject: Re: [Elecraft] K3 key-out jack - configuration needed? > Olli, > > The Key Out and the ACC connector Keyout-LP are developed from the same > internal signal, but the driving transistors are different for each. > The Key Out jack is driven by Q5 and Q3 on the RF Board, and you will > find your problem associated with one of those transistors. See the > schematic for the RF board at the top left of sheet 1. Check R4 as well > - the gate of Q3 should go to a high level during transmit (use TX test). > > 73, > Don W3FPR > > On 10/10/2010 10:31 AM, Oliver "Olli" Dröse wrote: >> Hi guys, >> >> preparing for the autumn contest season I thought to do some cable work >> today. >> Made up a cable to key the amplifier and wanted to use the key-out jack >> therefor >> (only need to sink 13,8 V / 60 mA so should work perfectly well). But the amp >> isn't keying. So I measured the RCA jack and unkeyed I can measure infinite >> resistance as it should be the case but if I ptt the radio no change on the >> RCA >> jack?! Should be around zero then so no keying there. >> >> Checked the manual but couldn't find anything related to configuration of >> that >> jack, seems it should be always working, right? Any ideas why it is not? >> >> Checked the LP key-out on the ACC connector and that is working properly (but >> not enough for the amp, ofcourse, only measured there for verification the >> radio >> is really keying out, hi). >> >> Can anybody help? >> >> TIA& 73, Olli - DH8BQA >> >> >> >> ______________________________________________________________ >> 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 >> -------------------------------------------------------------------------------- Eingehende eMail ist virenfrei. Von AVG überprüft - www.avg.de Version: 9.0.862 / Virendatenbank: 271.1.1/3187 - Ausgabedatum: 10/09/10 20:34:00 ______________________________________________________________ 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
