Dear Don & Group, Thanks for your suggestions. After some more exploration, I think the problem is the MH3 and here's why:
Backing down the mic gain didn't help and neither did a firmware reload. I was suspicious of the MH3 being at fault, as the ALC / Mic gain adjustment remained perfectly consistent and reliable in data modes. I then remembered I had a Yamaha CM500 headset lying in a drawer. I made an adapter (thanks Walter, K6WRU for your very helpful and clear webpage describing the adapter cable) I plugged it into the KX3 mic socket and lo and behold, the KX3 plays perfectly with it - the ALC shows 5-7 bars with a mic gain of 35-37 and I get the expected RF output, which is exactly how it used to be with the MH3. I took the MH3 apart and mechanically it all looks sound, no loose wires or dry joints, and I checked that there is indeed a bias voltage on the mic + ( tip) wire at the microphone. There's not much to go wrong in there, so I wonder if the electret element has died. I'll order a replacement MH3, because even though the CM500 headset works well, I like using the handmic and I've always had good audio reports using it. Thanks everyone for your interest. 73, John VK7JB -----Original Message----- From: Don Wilhelm [mailto:[email protected]] Sent: Sunday, 8 October 2017 11:09 To: Dr John H Farmer <[email protected]>; [email protected] Subject: Re: [Elecraft] KX3 SSB ALC Mic Gain - a new problem John, Try backing down the MIC Gain setting to something low or mid-range. If you get the mic voltage too high, the mic amplifier detects that and inserts attenuation that will shut the audio from the mic down. So bottom line, start with a low MIC Gain setting and increase it until you see 5 to 7 bars on the ALC meter. 73, Don W3FPR On 10/7/2017 7:53 PM, Dr John H Farmer wrote: > Yesterday, I noted that I had no RF output on SSB and find that now I > get no ALC indication until the Mic gain is advanced to the maximum setting > of 80. > Nothing else has changed in my > > setup. I've checked that MIC Bias is set to ON and the TX EQ settings > have not changed. I've also checked and there is indeed a bias > voltage on the Mic socket. ______________________________________________________________ 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]
