K3 Hum on transmit
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K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas?
73, Cary, K4TM Lynchburg VAh [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Try to use a car battery and check if the humm is still there, if yes than most likely is something inside the K3, if not than concentrate on PS. I've put on mine some big chocke on K3 DC input and I'm using SEC1223 with no hum problems
VE3GNO Daniel ________________________________ From: Hunsdon Cary III <[hidden email]> To: [hidden email] Cc: Wyatt Henry Wyatt <[hidden email]> Sent: Monday, January 23, 2012 10:10:50 AM Subject: [Elecraft] K3 Hum on transmit K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? 73, Cary, K4TM Lynchburg VAh [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Hunsdon Cary III
Cary,
Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. 73, Don W3FPR On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: > K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? > 73, > Cary, K4TM > Lynchburg VAh > [hidden email] > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Don:
You know it's hard to tell the difference between a buzz and a 60 hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected the mic front the front panel connector and used the XMIT button on the front panel, there is no buzz or hum! I'll start troubleshooting the mic cable now! Tnx for your help. 73, Cary, K4TM On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: > Cary, > > Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. > > Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. > > 73, > Don W3FPR > > On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: >> K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? >> 73, >> Cary, K4TM >> Lynchburg VAh >> [hidden email] >> >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> H. Cary III [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Cary,
I battled a hum/buzz problem just two weeks ago. After almost a full day spent hunting, experimenting, searching, and doing everything under the sun plus some very helpful dialog from others here on Elecraft forum, the hum/buzz was finally fixed. I did not fix it, it just disappeared. So, here are some things I did... (1) I did all my tests with the monitor on and TX in TEST mode since that in itself showed the hum/buzz. (2) With the help of Jim Brown (K9YC) I used the TX EQualization feature of the K3 to crimp down to minimum the low frequencies of the hum/buzz. Doing this, it appeared that this was indeed a buzz and not a 60-cycle hum because the buzz did not start to be attenuated until after the 400 Hz TXEQ was set to zero and I started working on the next higher frequency band. (3) I was confused as to whether this was front mic and back end mic inputs or just front. I finally determined that this was on the front mic only with 98 percent confidence. It is not 100 percent confidence because all of my experiments to prove one way or the other were a bit scrambled but I think this was front panel mic only. (4) I then focused on the mic itself, an Elecraft MH2 hand mic. Unfortunately it was the only mic I had for the front panel but if you have more then one then I definitely suggest you test them all to see if the hum/buzz is independent of mic. (5) I jiggled and bumped this front panel mic and connector to see if there was some loose connection. Someone suggested florescent lighting as a noise generated and I tested with all lights turned off (see next point). (6) I also had a nice 13.8 Li-nanoPhosphate battery so I disconnected EVERYTHING from the K3. The only two things connected were the 13.8 volt battery on the power and the mic on the front panel. No Antenna, no ground, no other connector to the K3. Hum/Buzz was still there and in that test I also turned off the circuit breaker for all AC in my shack. Did not help. (7) After some tests, and other things, the hum just seemed to disappear and never came back since. My best guess is that it was one of the following: (1) either an external noise source that eventually turned off and my front panel mic was just more susceptible to picking it up; or, (2) the front panel mic itself had some kind of loose connection that just seemed to finally correct itself. I favor cause (1) though. I am kind of hoping it comes back so I can test some more. 73, phil, K7PEH On Jan 23, 2012, at 7:37 AM, Hunsdon Cary III wrote: > Don: > You know it's hard to tell the difference between a buzz and a 60 hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected the mic front the front panel connector and used the XMIT button on the front panel, there is no buzz or hum! I'll start troubleshooting the mic cable now! > Tnx for your help. > 73, > Cary, K4TM > > On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: > >> Cary, >> >> Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. >> >> Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. >> >> 73, >> Don W3FPR >> >> On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: >>> K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? >>> 73, >>> Cary, K4TM >>> Lynchburg VAh >>> [hidden email] >>> >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> > > H. Cary III > [hidden email] > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Took the mic connector apart, even the Heil mic (gasp!). Could find no short on the connecting wires, although I did clip out the unused posts in the 8-pin connector. Put it back together, connected it to the K3 and, miraculously, like Phil, the hum/buzz is gone. Have no idea what I did, just glad it's gone after only 30" of effort!
Tnx for the help! 73, Cary, K4TM Sent from my iPhone in Lynchburg VA - named a Runner Friendly City by Road Runner's Club of America in 2011. On Jan 23, 2012, at 11:28 AM, Phil Hystad <[hidden email]> wrote: > Cary, > > I battled a hum/buzz problem just two weeks ago. After almost a full day spent hunting, experimenting, searching, and doing everything under the sun plus some very helpful dialog from others here on Elecraft forum, the hum/buzz was finally fixed. > > I did not fix it, it just disappeared. So, here are some things I did... > > (1) I did all my tests with the monitor on and TX in TEST mode since that in itself showed the hum/buzz. > > (2) With the help of Jim Brown (K9YC) I used the TX EQualization feature of the K3 to crimp down to minimum > the low frequencies of the hum/buzz. Doing this, it appeared that this was indeed a buzz and not a 60-cycle > hum because the buzz did not start to be attenuated until after the 400 Hz TXEQ was set to zero and I started > working on the next higher frequency band. > > (3) I was confused as to whether this was front mic and back end mic inputs or just front. I finally determined that > this was on the front mic only with 98 percent confidence. It is not 100 percent confidence because all of my > experiments to prove one way or the other were a bit scrambled but I think this was front panel mic only. > > (4) I then focused on the mic itself, an Elecraft MH2 hand mic. Unfortunately it was the only mic I had for the front > panel but if you have more then one then I definitely suggest you test them all to see if the hum/buzz is > independent of mic. > > (5) I jiggled and bumped this front panel mic and connector to see if there was some loose connection. Someone > suggested florescent lighting as a noise generated and I tested with all lights turned off (see next point). > > (6) I also had a nice 13.8 Li-nanoPhosphate battery so I disconnected EVERYTHING from the K3. The only two > things connected were the 13.8 volt battery on the power and the mic on the front panel. No Antenna, no > ground, no other connector to the K3. Hum/Buzz was still there and in that test I also turned off the circuit > breaker for all AC in my shack. Did not help. > > (7) After some tests, and other things, the hum just seemed to disappear and never came back since. My best > guess is that it was one of the following: (1) either an external noise source that eventually turned off and > my front panel mic was just more susceptible to picking it up; or, (2) the front panel mic itself had some kind > of loose connection that just seemed to finally correct itself. I favor cause (1) though. I am kind of hoping it > comes back so I can test some more. > > 73, phil, K7PEH > > > On Jan 23, 2012, at 7:37 AM, Hunsdon Cary III wrote: > >> Don: >> You know it's hard to tell the difference between a buzz and a 60 hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected the mic front the front panel connector and used the XMIT button on the front panel, there is no buzz or hum! I'll start troubleshooting the mic cable now! >> Tnx for your help. >> 73, >> Cary, K4TM >> >> On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: >> >>> Cary, >>> >>> Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. >>> >>> Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. >>> >>> 73, >>> Don W3FPR >>> >>> On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: >>>> K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? >>>> 73, >>>> Cary, K4TM >>>> Lynchburg VAh >>>> [hidden email] >>>> >>>> >>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >> >> H. Cary III >> [hidden email] >> >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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I had the same problem with Heil Proset, finally in an angry moment I
hit the mike to the desk and problem went away probably temporarily. I have not found error nor in the K3 mic grounding, neither in the Proset capsule wiring. Wanted to buy new mic element, no answer from Heil. Still question. 72' István Szabó On 1/23/2012 6:31 PM, Hunsdon Cary III wrote: > Took the mic connector apart, even the Heil mic (gasp!). Could find no short on the connecting wires, although I did clip out the unused posts in the 8-pin connector. Put it back together, connected it to the K3 and, miraculously, like Phil, the hum/buzz is gone. Have no idea what I did, just glad it's gone after only 30" of effort! > Tnx for the help! > 73, > Cary, K4TM > > Sent from my iPhone in Lynchburg VA - named a Runner Friendly City by Road Runner's Club of America in 2011. > > > On Jan 23, 2012, at 11:28 AM, Phil Hystad<[hidden email]> wrote: > >> Cary, >> >> I battled a hum/buzz problem just two weeks ago. After almost a full day spent hunting, experimenting, searching, and doing everything under the sun plus some very helpful dialog from others here on Elecraft forum, the hum/buzz was finally fixed. >> >> I did not fix it, it just disappeared. So, here are some things I did... >> >> (1) I did all my tests with the monitor on and TX in TEST mode since that in itself showed the hum/buzz. >> >> (2) With the help of Jim Brown (K9YC) I used the TX EQualization feature of the K3 to crimp down to minimum >> the low frequencies of the hum/buzz. Doing this, it appeared that this was indeed a buzz and not a 60-cycle >> hum because the buzz did not start to be attenuated until after the 400 Hz TXEQ was set to zero and I started >> working on the next higher frequency band. >> >> (3) I was confused as to whether this was front mic and back end mic inputs or just front. I finally determined that >> this was on the front mic only with 98 percent confidence. It is not 100 percent confidence because all of my >> experiments to prove one way or the other were a bit scrambled but I think this was front panel mic only. >> >> (4) I then focused on the mic itself, an Elecraft MH2 hand mic. Unfortunately it was the only mic I had for the front >> panel but if you have more then one then I definitely suggest you test them all to see if the hum/buzz is >> independent of mic. >> >> (5) I jiggled and bumped this front panel mic and connector to see if there was some loose connection. Someone >> suggested florescent lighting as a noise generated and I tested with all lights turned off (see next point). >> >> (6) I also had a nice 13.8 Li-nanoPhosphate battery so I disconnected EVERYTHING from the K3. The only two >> things connected were the 13.8 volt battery on the power and the mic on the front panel. No Antenna, no >> ground, no other connector to the K3. Hum/Buzz was still there and in that test I also turned off the circuit >> breaker for all AC in my shack. Did not help. >> >> (7) After some tests, and other things, the hum just seemed to disappear and never came back since. My best >> guess is that it was one of the following: (1) either an external noise source that eventually turned off and >> my front panel mic was just more susceptible to picking it up; or, (2) the front panel mic itself had some kind >> of loose connection that just seemed to finally correct itself. I favor cause (1) though. I am kind of hoping it >> comes back so I can test some more. >> >> 73, phil, K7PEH >> >> >> On Jan 23, 2012, at 7:37 AM, Hunsdon Cary III wrote: >> >>> Don: >>> You know it's hard to tell the difference between a buzz and a 60 hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected the mic front the front panel connector and used the XMIT button on the front panel, there is no buzz or hum! I'll start troubleshooting the mic cable now! >>> Tnx for your help. >>> 73, >>> Cary, K4TM >>> >>> On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: >>> >>>> Cary, >>>> >>>> Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. >>>> >>>> Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. >>>> >>>> 73, >>>> Don W3FPR >>>> >>>> On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: >>>>> K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? >>>>> 73, >>>>> Cary, K4TM >>>>> Lynchburg VAh >>>>> [hidden email] >>>>> >>>>> >>>>> >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[hidden email] >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>> H. Cary III >>> [hidden email] >>> >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Given ROHS and the new world of lead-free solder that does not always "wet"
to wire or pins, you may find it useful on a mic to reheat ALL the solder joints in the plug AND in the microphone housing. Microphones are a very low margin item, and everyone is getting them made CHEEP somewhere. There are no tests to measure "just barely soldered" connections, where the actual connection is only a handful of molecules wide. I have not gotten to the point where I do that routinely to brand-new microphones, but I am sorely tempted. Microphone cords, per se, can wear out faster than socks. Power supply makers spend millions of dollars of research dollars to make power supplies even cheaper than they are now. You want to see cheap, flimsy sh*t just crack open your power supply, especially if you were looking for best price. They have made a science of not putting in anything unless it was absolutely necessary. They are PLANNING on a certain level of warranty returns and have that VERY carefully balanced against lowest quality (cost) components in a COST-ONLY equation. Careful whom or what you implicitly trust. The one disgusting parallel comes from the old admonition to not visit the sausage line at a meat-packing factory. Their strategy depends on your ignorance. Always remember, tear apart your K3 DEAD LAST after EVERYTHING ELSE is ruled out. Most of the things we think are wrong with the transceiver are external. You can learn that hard or you can learn that easy. 73, Guy 2012/1/23 István Szabó <[hidden email]> > I had the same problem with Heil Proset, finally in an angry moment I > hit the mike to the desk and problem went away probably temporarily. I > have not found error nor in the K3 mic grounding, neither in the Proset > capsule wiring. Wanted to buy new mic element, no answer from Heil. > Still question. > > 72' > > István Szabó > > > > On 1/23/2012 6:31 PM, Hunsdon Cary III wrote: > > Took the mic connector apart, even the Heil mic (gasp!). Could find no > short on the connecting wires, although I did clip out the unused posts in > the 8-pin connector. Put it back together, connected it to the K3 and, > miraculously, like Phil, the hum/buzz is gone. Have no idea what I did, > just glad it's gone after only 30" of effort! > > Tnx for the help! > > 73, > > Cary, K4TM > > > > Sent from my iPhone in Lynchburg VA - named a Runner Friendly City by > Road Runner's Club of America in 2011. > > > > > > On Jan 23, 2012, at 11:28 AM, Phil Hystad<[hidden email]> wrote: > > > >> Cary, > >> > >> I battled a hum/buzz problem just two weeks ago. After almost a full > day spent hunting, experimenting, searching, and doing everything under the > sun plus some very helpful dialog from others here on Elecraft forum, the > hum/buzz was finally fixed. > >> > >> I did not fix it, it just disappeared. So, here are some things I > did... > >> > >> (1) I did all my tests with the monitor on and TX in TEST mode since > that in itself showed the hum/buzz. > >> > >> (2) With the help of Jim Brown (K9YC) I used the TX EQualization > feature of the K3 to crimp down to minimum > >> the low frequencies of the hum/buzz. Doing this, it appeared > that this was indeed a buzz and not a 60-cycle > >> hum because the buzz did not start to be attenuated until after > the 400 Hz TXEQ was set to zero and I started > >> working on the next higher frequency band. > >> > >> (3) I was confused as to whether this was front mic and back end mic > inputs or just front. I finally determined that > >> this was on the front mic only with 98 percent confidence. It is > not 100 percent confidence because all of my > >> experiments to prove one way or the other were a bit scrambled > but I think this was front panel mic only. > >> > >> (4) I then focused on the mic itself, an Elecraft MH2 hand mic. > Unfortunately it was the only mic I had for the front > >> panel but if you have more then one then I definitely suggest you > test them all to see if the hum/buzz is > >> independent of mic. > >> > >> (5) I jiggled and bumped this front panel mic and connector to see if > there was some loose connection. Someone > >> suggested florescent lighting as a noise generated and I tested > with all lights turned off (see next point). > >> > >> (6) I also had a nice 13.8 Li-nanoPhosphate battery so I disconnected > EVERYTHING from the K3. The only two > >> things connected were the 13.8 volt battery on the power and the > mic on the front panel. No Antenna, no > >> ground, no other connector to the K3. Hum/Buzz was still there > and in that test I also turned off the circuit > >> breaker for all AC in my shack. Did not help. > >> > >> (7) After some tests, and other things, the hum just seemed to > disappear and never came back since. My best > >> guess is that it was one of the following: (1) either an > external noise source that eventually turned off and > >> my front panel mic was just more susceptible to picking it up; > or, (2) the front panel mic itself had some kind > >> of loose connection that just seemed to finally correct itself. > I favor cause (1) though. I am kind of hoping it > >> comes back so I can test some more. > >> > >> 73, phil, K7PEH > >> > >> > >> On Jan 23, 2012, at 7:37 AM, Hunsdon Cary III wrote: > >> > >>> Don: > >>> You know it's hard to tell the difference between a buzz and a 60 > hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected > the mic front the front panel connector and used the XMIT button on the > front panel, there is no buzz or hum! I'll start troubleshooting the mic > cable now! > >>> Tnx for your help. > >>> 73, > >>> Cary, K4TM > >>> > >>> On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: > >>> > >>>> Cary, > >>>> > >>>> Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will > be of various frequencies, and it is difficult to tell them apart with just > your ears as detectors. > >>>> > >>>> Does it disappear if the microphone is not connected? Use XMIT to > put the K3 in transmit while you are listening. If it is only when the > microphone is connected, you may have a broken wire in the mic cable. > >>>> > >>>> 73, > >>>> Don W3FPR > >>>> > >>>> On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: > >>>>> K3 Experts: My K3-100 has been flawless in its performance until > yesterday. I had a schedule with W5ZNN who told me I had a hum on my > signal; I put my headphones on and sure enough there it was on transmit. I > tried plugging the Astron 35M directly into the AC outlet instead of the > outlet strip - no luck, hum was still there. I connected the K3 to my SEC > 1223 switching power supply and, you guessed it, the hum is still there. I > hate to think there's something amiss with the K3 but it looks that way. > Any ideas? > >>>>> 73, > >>>>> Cary, K4TM > >>>>> Lynchburg VAh > >>>>> [hidden email] > >>>>> > >>>>> > >>>>> > >>>>> ______________________________________________________________ > >>>>> Elecraft mailing list > >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >>>>> Help: http://mailman.qth.net/mmfaq.htm > >>>>> Post: mailto:[hidden email] > >>>>> > >>>>> This list hosted by: http://www.qsl.net > >>>>> Please help support this email list: http://www.qsl.net/donate.html > >>>>> > >>> H. Cary III > >>> [hidden email] > >>> > >>> > >>> > >>> ______________________________________________________________ > >>> Elecraft mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:[hidden email] > >>> > >>> This list hosted by: http://www.qsl.net > >>> Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Phil Hystad-3
I have found, on occasion, I get a raspy pulsing noise on the audio. I
believe it is coming from a USB connection through an audio switching device. I must make sure the RS232 plug on the back of the K3 is securely screwed on (not just pushed on) and wiggling the audio plugs in the row below the RS232 and the ACC jacks will make it go away. I haven't figured out exactly which one it is yet. The K3 is star-point grounded with the computer case but not the audio switching device. I have done the pin1 mic mod. The plugs are one more thing to check as you look for the source of your "hum." Buck k4ia On 1/23/2012 11:28 AM, Phil Hystad wrote: > Cary, > > I battled a hum/buzz problem just two weeks ago. After almost a full day spent hunting, experimenting, searching, and doing everything under the sun plus some very helpful dialog from others here on Elecraft forum, the hum/buzz was finally fixed. > > I did not fix it, it just disappeared. So, here are some things I did... > > (1) I did all my tests with the monitor on and TX in TEST mode since that in itself showed the hum/buzz. > > (2) With the help of Jim Brown (K9YC) I used the TX EQualization feature of the K3 to crimp down to minimum > the low frequencies of the hum/buzz. Doing this, it appeared that this was indeed a buzz and not a 60-cycle > hum because the buzz did not start to be attenuated until after the 400 Hz TXEQ was set to zero and I started > working on the next higher frequency band. > > (3) I was confused as to whether this was front mic and back end mic inputs or just front. I finally determined that > this was on the front mic only with 98 percent confidence. It is not 100 percent confidence because all of my > experiments to prove one way or the other were a bit scrambled but I think this was front panel mic only. > > (4) I then focused on the mic itself, an Elecraft MH2 hand mic. Unfortunately it was the only mic I had for the front > panel but if you have more then one then I definitely suggest you test them all to see if the hum/buzz is > independent of mic. > > (5) I jiggled and bumped this front panel mic and connector to see if there was some loose connection. Someone > suggested florescent lighting as a noise generated and I tested with all lights turned off (see next point). > > (6) I also had a nice 13.8 Li-nanoPhosphate battery so I disconnected EVERYTHING from the K3. The only two > things connected were the 13.8 volt battery on the power and the mic on the front panel. No Antenna, no > ground, no other connector to the K3. Hum/Buzz was still there and in that test I also turned off the circuit > breaker for all AC in my shack. Did not help. > > (7) After some tests, and other things, the hum just seemed to disappear and never came back since. My best > guess is that it was one of the following: (1) either an external noise source that eventually turned off and > my front panel mic was just more susceptible to picking it up; or, (2) the front panel mic itself had some kind > of loose connection that just seemed to finally correct itself. I favor cause (1) though. I am kind of hoping it > comes back so I can test some more. > > 73, phil, K7PEH > > > On Jan 23, 2012, at 7:37 AM, Hunsdon Cary III wrote: > >> Don: >> You know it's hard to tell the difference between a buzz and a 60 hertz hum, at least to my 66 year old ears. HOWEVER, when I disconnected the mic front the front panel connector and used the XMIT button on the front panel, there is no buzz or hum! I'll start troubleshooting the mic cable now! >> Tnx for your help. >> 73, >> Cary, K4TM >> >> On Jan 23, 2012, at 10:23 AM, Don Wilhelm wrote: >> >>> Cary, >>> >>> Is it hum or is it actually "buzz"? Hum is 60 Hz AC, but buzz will be of various frequencies, and it is difficult to tell them apart with just your ears as detectors. >>> >>> Does it disappear if the microphone is not connected? Use XMIT to put the K3 in transmit while you are listening. If it is only when the microphone is connected, you may have a broken wire in the mic cable. >>> >>> 73, >>> Don W3FPR >>> >>> On 1/23/2012 10:10 AM, Hunsdon Cary III wrote: >>>> K3 Experts: My K3-100 has been flawless in its performance until yesterday. I had a schedule with W5ZNN who told me I had a hum on my signal; I put my headphones on and sure enough there it was on transmit. I tried plugging the Astron 35M directly into the AC outlet instead of the outlet strip - no luck, hum was still there. I connected the K3 to my SEC 1223 switching power supply and, you guessed it, the hum is still there. I hate to think there's something amiss with the K3 but it looks that way. Any ideas? >>>> 73, >>>> Cary, K4TM >>>> Lynchburg VAh >>>> [hidden email] >>>> >>>> >>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >> H. Cary III >> [hidden email] >> >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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