K3 speaker audio gone!
Locked
 
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I've lost audio from both the internal speaker in the K3,
and from the SPKRS output jack on the rear panel. At the end of the the first week of using a new NESCAF audio filter (which drives my speaker) with the K3, I changed bands, listened briefly on CW, with the NESCAF filter in the circuit. I then changed to SSB, and because the NESCAF filter was adjusted for a very narrow audio bandwidth, I decided to switch it out of the circuit, while the K3 was delivering audio, at a comfortable listening level.. The audio filter was driven from the SPKRS jack on the back of the K3, using a stereo plug, with one channel floating. The SPKRS jack was CONFIGured as SPKRS = 1. A front panel toggle switch on the filter panel turns off the power to the NESCAF filter, and re-routes the speaker audio connection from the filter output, to the K3 output directly. I had done this often, for the first week of operations. This time, however, I briefly saw a "HI CURR" indication on the front panel of the K3, and then my speaker audio vanished. Unplugging all connections from the rear panel SPKRS jack, and the front panel PHONES jack, no longer allows the K3's internal speaker to produce audio. Nothing I tried would result in any audio from the external speaker, after connecting that speaker to either of the phono jacks that were tied to the rear SPKRS jack, through the stereo plug. The INPUT jack on the SCAF filter (to which the K3's SPKRS jack was connected) passes through an isolating capacitor, then a 27K resistor, before being connected to the chip in the audio filter. Resetting SPRKS = 2, in the CONFIG menu, had no effect on producing audio in the external, or internal speaker. I still have audio at the PHONES jack on the front panel, so I can still use the K3. It subsequently accounted for 380 QSOs in the NAQP CW contest, providing it usual flawless performance. I still have audio at the PHONES jack on the rear panel, as well. My theory (and Gary at Elecraft Service agrees it might be the cause) is that the audio chip in the K3 didn't like the abrupt change of load impedance, from 27K (approx.) to infinity, to 8 ohms, while it was delivering audio.. I've since soldered a 15K resistor across the input jack of the audio filter, and will do likewise for any other audio filters I encounter, and use. Puzzling, huh? 73 de VE3GFN ______________________________________________________________ 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 have blown the speaker amp twice, in two different radios, by
using a speaker with AGC OFF. POOF! Gone before you can react by turning down the audio. The factory guys report that they have been unable to duplicate the problem. Unless you are an EXPERT solderer, replacing the speaker amp chip is best done by the factory. The job will run about $125 with shipping, maybe a little less if you ship only the DSP Board. I don't use the speaker amp any more. I still think there is a transient susceptibility problem in that circuitry that they have been unable to find. Dave Hachadorian, K6LL Big Bear Lake, California -----Original Message----- From: Mike Goldstein Sent: Tuesday, August 28, 2012 9:07 AM To: [hidden email] Subject: [Elecraft] K3 speaker audio gone! I've lost audio from both the internal speaker in the K3, and from the SPKRS output jack on the rear panel. At the end of the the first week of using a new NESCAF audio filter (which drives my speaker) with the K3, I changed bands, listened briefly on CW, with the NESCAF filter in the circuit. I then changed to SSB, and because the NESCAF filter was adjusted for a very narrow audio bandwidth, I decided to switch it out of the circuit, while the K3 was delivering audio, at a comfortable listening level.. The audio filter was driven from the SPKRS jack on the back of the K3, using a stereo plug, with one channel floating. The SPKRS jack was CONFIGured as SPKRS = 1. A front panel toggle switch on the filter panel turns off the power to the NESCAF filter, and re-routes the speaker audio connection from the filter output, to the K3 output directly. I had done this often, for the first week of operations. This time, however, I briefly saw a "HI CURR" indication on the front panel of the K3, and then my speaker audio vanished. Unplugging all connections from the rear panel SPKRS jack, and the front panel PHONES jack, no longer allows the K3's internal speaker to produce audio. Nothing I tried would result in any audio from the external speaker, after connecting that speaker to either of the phono jacks that were tied to the rear SPKRS jack, through the stereo plug. The INPUT jack on the SCAF filter (to which the K3's SPKRS jack was connected) passes through an isolating capacitor, then a 27K resistor, before being connected to the chip in the audio filter. Resetting SPRKS = 2, in the CONFIG menu, had no effect on producing audio in the external, or internal speaker. I still have audio at the PHONES jack on the front panel, so I can still use the K3. It subsequently accounted for 380 QSOs in the NAQP CW contest, providing it usual flawless performance. I still have audio at the PHONES jack on the rear panel, as well. My theory (and Gary at Elecraft Service agrees it might be the cause) is that the audio chip in the K3 didn't like the abrupt change of load impedance, from 27K (approx.) to infinity, to 8 ohms, while it was delivering audio.. I've since soldered a 15K resistor across the input jack of the audio filter, and will do likewise for any other audio filters I encounter, and use. Puzzling, huh? 73 de VE3GFN ______________________________________________________________ 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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Dave,
Do you have the AF amp current-limiting mod in place? The parts for this mod are installed on the RF board. They've been in production for quite some time, and we can send them to you on request. With the limiter installed, we've seen near-zero problems with the AF amp IC. 73, Wayne N6KR On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: > I have blown the speaker amp twice, in two different radios, by > using a speaker with AGC OFF. POOF! Gone before you can react by > turning down the audio. > > The factory guys report that they have been unable to duplicate > the problem. Unless you are an EXPERT solderer, replacing the > speaker amp chip is best done by the factory. The job will run > about $125 with shipping, maybe a little less if you ship only > the DSP Board. I don't use the speaker amp any more. I still > think there is a transient susceptibility problem in that > circuitry that they have been unable to find. > > > Dave Hachadorian, K6LL > Big Bear Lake, California > > > > > > > -----Original Message----- > From: Mike Goldstein > Sent: Tuesday, August 28, 2012 9:07 AM > To: [hidden email] > Subject: [Elecraft] K3 speaker audio gone! > > I've lost audio from both the internal speaker in the > K3, > and from the SPKRS output jack on the rear panel. > > At the end of the the first week of using a new NESCAF > audio > filter (which drives my speaker) with the K3, I changed bands, > listened briefly on CW, with the NESCAF filter in the circuit. I > then changed to SSB, and because the NESCAF filter was adjusted > for a > very narrow audio bandwidth, I decided to switch it out of the > circuit, while the K3 was delivering audio, at a comfortable > listening level.. > > The audio filter was driven from the SPKRS jack on the > back > of the K3, using a stereo plug, with one channel floating. The > SPKRS > jack was CONFIGured as SPKRS = 1. > > A front panel toggle switch on the filter panel turns off the > power > to the NESCAF filter, and re-routes the speaker audio connection > from > the filter output, to the K3 output directly. I had done this > often, > for the first week of operations. > > This time, however, I briefly saw a "HI CURR" indication on the > front > panel of the K3, and then my speaker audio vanished. > > Unplugging all connections from the rear panel SPKRS jack, and > the > front panel PHONES jack, no longer allows the K3's internal > speaker > to produce audio. Nothing I tried would result in any audio from > the > external speaker, after connecting that speaker to either of the > phono jacks that were tied to the rear SPKRS jack, through the > stereo plug. > > The INPUT jack on the SCAF filter (to which the K3's SPKRS jack > was > connected) passes through an isolating capacitor, then a 27K > resistor, before being connected to the chip in the audio filter. > > Resetting SPRKS = 2, in the CONFIG menu, had no effect on > producing > audio in the external, or internal speaker. > > I still have audio at the PHONES jack on the front panel, so I > can > still use the K3. It subsequently accounted for 380 QSOs in the > NAQP > CW contest, providing it usual flawless performance. > > I still have audio at the PHONES jack on the rear panel, as well. > > My theory (and Gary at Elecraft Service agrees it might be the > cause) > is that the audio chip in the K3 didn't like the abrupt change of > load impedance, from 27K (approx.) to infinity, to 8 ohms, while > it > was delivering audio.. > > I've since soldered a 15K resistor across the input jack of the > audio > filter, and will do likewise for any other audio filters I > encounter, and use. > > Puzzling, huh? 73 de VE3GFN > ______________________________________________________________ > 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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Was there a serial # that included the current limiting?
Sent from my iPhone On Aug 28, 2012, at 1:18 PM, "Wayne Burdick" <[hidden email]> wrote: > Dave, > > Do you have the AF amp current-limiting mod in place? The parts for > this mod are installed on the RF board. They've been in production for > quite some time, and we can send them to you on request. > > With the limiter installed, we've seen near-zero problems with the AF > amp IC. > > 73, > Wayne > N6KR > > > > On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: > >> I have blown the speaker amp twice, in two different radios, by >> using a speaker with AGC OFF. POOF! Gone before you can react by >> turning down the audio. >> >> The factory guys report that they have been unable to duplicate >> the problem. Unless you are an EXPERT solderer, replacing the >> speaker amp chip is best done by the factory. The job will run >> about $125 with shipping, maybe a little less if you ship only >> the DSP Board. I don't use the speaker amp any more. I still >> think there is a transient susceptibility problem in that >> circuitry that they have been unable to find. >> >> >> Dave Hachadorian, K6LL >> Big Bear Lake, California >> >> >> >> >> >> >> -----Original Message----- >> From: Mike Goldstein >> Sent: Tuesday, August 28, 2012 9:07 AM >> To: [hidden email] >> Subject: [Elecraft] K3 speaker audio gone! >> >> I've lost audio from both the internal speaker in the >> K3, >> and from the SPKRS output jack on the rear panel. >> >> At the end of the the first week of using a new NESCAF >> audio >> filter (which drives my speaker) with the K3, I changed bands, >> listened briefly on CW, with the NESCAF filter in the circuit. I >> then changed to SSB, and because the NESCAF filter was adjusted >> for a >> very narrow audio bandwidth, I decided to switch it out of the >> circuit, while the K3 was delivering audio, at a comfortable >> listening level.. >> >> The audio filter was driven from the SPKRS jack on the >> back >> of the K3, using a stereo plug, with one channel floating. The >> SPKRS >> jack was CONFIGured as SPKRS = 1. >> >> A front panel toggle switch on the filter panel turns off the >> power >> to the NESCAF filter, and re-routes the speaker audio connection >> from >> the filter output, to the K3 output directly. I had done this >> often, >> for the first week of operations. >> >> This time, however, I briefly saw a "HI CURR" indication on the >> front >> panel of the K3, and then my speaker audio vanished. >> >> Unplugging all connections from the rear panel SPKRS jack, and >> the >> front panel PHONES jack, no longer allows the K3's internal >> speaker >> to produce audio. Nothing I tried would result in any audio from >> the >> external speaker, after connecting that speaker to either of the >> phono jacks that were tied to the rear SPKRS jack, through the >> stereo plug. >> >> The INPUT jack on the SCAF filter (to which the K3's SPKRS jack >> was >> connected) passes through an isolating capacitor, then a 27K >> resistor, before being connected to the chip in the audio filter. >> >> Resetting SPRKS = 2, in the CONFIG menu, had no effect on >> producing >> audio in the external, or internal speaker. >> >> I still have audio at the PHONES jack on the front panel, so I >> can >> still use the K3. It subsequently accounted for 380 QSOs in the >> NAQP >> CW contest, providing it usual flawless performance. >> >> I still have audio at the PHONES jack on the rear panel, as well. >> >> My theory (and Gary at Elecraft Service agrees it might be the >> cause) >> is that the audio chip in the K3 didn't like the abrupt change of >> load impedance, from 27K (approx.) to infinity, to 8 ohms, while >> it >> was delivering audio.. >> >> I've since soldered a 15K resistor across the input jack of the >> audio >> filter, and will do likewise for any other audio filters I >> encounter, and use. >> >> Puzzling, huh? 73 de VE3GFN >> ______________________________________________________________ >> 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
Chuck, KE9UW
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Re: K3 speaker audio gone!
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See: http://www.elecraft.com/K3/mods/AF_Output_Mod_Rev_C.pdf
"This modification is needed for all K3s shipped to date containing either a Revision XB or Revision A KIO3 board. You must inspect the KIO3 board to see whether the modification has been made. Modified boards will include the leaded resistors shown in Figure 4. You can see the resistor in the lower part of the figure by removing the top cover as shown in Figure 1 and inspecting the side of the KIO3 board facing away from the rear panel. " Also http://www.elecraft.com/K3/k3_app_notes.htm states "Included on all new K3s About 12/23/08 and later." 73, ~iain / N6ML On Tue, Aug 28, 2012 at 11:31 AM, hawley, charles j jr <[hidden email]> wrote: > Was there a serial # that included the current limiting? > > Sent from my iPhone > > On Aug 28, 2012, at 1:18 PM, "Wayne Burdick" <[hidden email]> wrote: > >> Dave, >> >> Do you have the AF amp current-limiting mod in place? The parts for >> this mod are installed on the RF board. They've been in production for >> quite some time, and we can send them to you on request. >> >> With the limiter installed, we've seen near-zero problems with the AF >> amp IC. >> >> 73, >> Wayne >> N6KR >> >> >> >> On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: >> >>> I have blown the speaker amp twice, in two different radios, by >>> using a speaker with AGC OFF. POOF! Gone before you can react by >>> turning down the audio. >>> >>> The factory guys report that they have been unable to duplicate >>> the problem. Unless you are an EXPERT solderer, replacing the >>> speaker amp chip is best done by the factory. The job will run >>> about $125 with shipping, maybe a little less if you ship only >>> the DSP Board. I don't use the speaker amp any more. I still >>> think there is a transient susceptibility problem in that >>> circuitry that they have been unable to find. >>> >>> >>> Dave Hachadorian, K6LL >>> Big Bear Lake, California >>> >>> >>> >>> >>> >>> >>> -----Original Message----- >>> From: Mike Goldstein >>> Sent: Tuesday, August 28, 2012 9:07 AM >>> To: [hidden email] >>> Subject: [Elecraft] K3 speaker audio gone! >>> >>> I've lost audio from both the internal speaker in the >>> K3, >>> and from the SPKRS output jack on the rear panel. >>> >>> At the end of the the first week of using a new NESCAF >>> audio >>> filter (which drives my speaker) with the K3, I changed bands, >>> listened briefly on CW, with the NESCAF filter in the circuit. I >>> then changed to SSB, and because the NESCAF filter was adjusted >>> for a >>> very narrow audio bandwidth, I decided to switch it out of the >>> circuit, while the K3 was delivering audio, at a comfortable >>> listening level.. >>> >>> The audio filter was driven from the SPKRS jack on the >>> back >>> of the K3, using a stereo plug, with one channel floating. The >>> SPKRS >>> jack was CONFIGured as SPKRS = 1. >>> >>> A front panel toggle switch on the filter panel turns off the >>> power >>> to the NESCAF filter, and re-routes the speaker audio connection >>> from >>> the filter output, to the K3 output directly. I had done this >>> often, >>> for the first week of operations. >>> >>> This time, however, I briefly saw a "HI CURR" indication on the >>> front >>> panel of the K3, and then my speaker audio vanished. >>> >>> Unplugging all connections from the rear panel SPKRS jack, and >>> the >>> front panel PHONES jack, no longer allows the K3's internal >>> speaker >>> to produce audio. Nothing I tried would result in any audio from >>> the >>> external speaker, after connecting that speaker to either of the >>> phono jacks that were tied to the rear SPKRS jack, through the >>> stereo plug. >>> >>> The INPUT jack on the SCAF filter (to which the K3's SPKRS jack >>> was >>> connected) passes through an isolating capacitor, then a 27K >>> resistor, before being connected to the chip in the audio filter. >>> >>> Resetting SPRKS = 2, in the CONFIG menu, had no effect on >>> producing >>> audio in the external, or internal speaker. >>> >>> I still have audio at the PHONES jack on the front panel, so I >>> can >>> still use the K3. It subsequently accounted for 380 QSOs in the >>> NAQP >>> CW contest, providing it usual flawless performance. >>> >>> I still have audio at the PHONES jack on the rear panel, as well. >>> >>> My theory (and Gary at Elecraft Service agrees it might be the >>> cause) >>> is that the audio chip in the K3 didn't like the abrupt change of >>> load impedance, from 27K (approx.) to infinity, to 8 ohms, while >>> it >>> was delivering audio.. >>> >>> I've since soldered a 15K resistor across the input jack of the >>> audio >>> filter, and will do likewise for any other audio filters I >>> encounter, and use. >>> >>> Puzzling, huh? 73 de VE3GFN >>> ______________________________________________________________ >>> 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 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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Administrator
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Iain,
The mod you referenced below is a very old one (470 ohm resistors on the KIO3). It has been in production for a long time. The mod I was talking about is newer (2010, I believe). It involves a pair of very small-valued resistors in series with the AF output coupling capacitors. This, too, is in production. However, I just looked on the K3 mods page, and it appears that we never did turn this into a mod kit. We'll get this corrected right away. Wayne N6KR On Aug 28, 2012, at 12:17 PM, iain macdonnell - N6ML wrote: > See: http://www.elecraft.com/K3/mods/AF_Output_Mod_Rev_C.pdf > > "This modification is needed for all K3s shipped to date containing > either a Revision XB or Revision A KIO3 > board. You must inspect the KIO3 board to see whether the modification > has been made. Modified boards will > include the leaded resistors shown in Figure 4. You can see the > resistor in the lower part of the figure by removing > the top cover as shown in Figure 1 and inspecting the side of the KIO3 > board facing away from the rear panel. " > > Also http://www.elecraft.com/K3/k3_app_notes.htm states "Included on > all new K3s About 12/23/08 and later." > > 73, > > ~iain / N6ML > > > On Tue, Aug 28, 2012 at 11:31 AM, hawley, charles j jr > <[hidden email]> wrote: >> Was there a serial # that included the current limiting? >> >> Sent from my iPhone >> >> On Aug 28, 2012, at 1:18 PM, "Wayne Burdick" <[hidden email]> >> wrote: >> >>> Dave, >>> >>> Do you have the AF amp current-limiting mod in place? The parts for >>> this mod are installed on the RF board. They've been in production >>> for >>> quite some time, and we can send them to you on request. >>> >>> With the limiter installed, we've seen near-zero problems with the >>> AF >>> amp IC. >>> >>> 73, >>> Wayne >>> N6KR >>> >>> >>> >>> On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: >>> >>>> I have blown the speaker amp twice, in two different radios, by >>>> using a speaker with AGC OFF. POOF! Gone before you can react by >>>> turning down the audio. >>>> >>>> The factory guys report that they have been unable to duplicate >>>> the problem. Unless you are an EXPERT solderer, replacing the >>>> speaker amp chip is best done by the factory. The job will run >>>> about $125 with shipping, maybe a little less if you ship only >>>> the DSP Board. I don't use the speaker amp any more. I still >>>> think there is a transient susceptibility problem in that >>>> circuitry that they have been unable to find. >>>> >>>> >>>> Dave Hachadorian, K6LL >>>> Big Bear Lake, California >>>> >>>> >>>> >>>> >>>> >>>> >>>> -----Original Message----- >>>> From: Mike Goldstein >>>> Sent: Tuesday, August 28, 2012 9:07 AM >>>> To: [hidden email] >>>> Subject: [Elecraft] K3 speaker audio gone! >>>> >>>> I've lost audio from both the internal speaker in the >>>> K3, >>>> and from the SPKRS output jack on the rear panel. >>>> >>>> At the end of the the first week of using a new NESCAF >>>> audio >>>> filter (which drives my speaker) with the K3, I changed bands, >>>> listened briefly on CW, with the NESCAF filter in the circuit. I >>>> then changed to SSB, and because the NESCAF filter was adjusted >>>> for a >>>> very narrow audio bandwidth, I decided to switch it out of the >>>> circuit, while the K3 was delivering audio, at a comfortable >>>> listening level.. >>>> >>>> The audio filter was driven from the SPKRS jack on the >>>> back >>>> of the K3, using a stereo plug, with one channel floating. The >>>> SPKRS >>>> jack was CONFIGured as SPKRS = 1. >>>> >>>> A front panel toggle switch on the filter panel turns off the >>>> power >>>> to the NESCAF filter, and re-routes the speaker audio connection >>>> from >>>> the filter output, to the K3 output directly. I had done this >>>> often, >>>> for the first week of operations. >>>> >>>> This time, however, I briefly saw a "HI CURR" indication on the >>>> front >>>> panel of the K3, and then my speaker audio vanished. >>>> >>>> Unplugging all connections from the rear panel SPKRS jack, and >>>> the >>>> front panel PHONES jack, no longer allows the K3's internal >>>> speaker >>>> to produce audio. Nothing I tried would result in any audio from >>>> the >>>> external speaker, after connecting that speaker to either of the >>>> phono jacks that were tied to the rear SPKRS jack, through the >>>> stereo plug. >>>> >>>> The INPUT jack on the SCAF filter (to which the K3's SPKRS jack >>>> was >>>> connected) passes through an isolating capacitor, then a 27K >>>> resistor, before being connected to the chip in the audio filter. >>>> >>>> Resetting SPRKS = 2, in the CONFIG menu, had no effect on >>>> producing >>>> audio in the external, or internal speaker. >>>> >>>> I still have audio at the PHONES jack on the front panel, so I >>>> can >>>> still use the K3. It subsequently accounted for 380 QSOs in the >>>> NAQP >>>> CW contest, providing it usual flawless performance. >>>> >>>> I still have audio at the PHONES jack on the rear panel, as well. >>>> >>>> My theory (and Gary at Elecraft Service agrees it might be the >>>> cause) >>>> is that the audio chip in the K3 didn't like the abrupt change of >>>> load impedance, from 27K (approx.) to infinity, to 8 ohms, while >>>> it >>>> was delivering audio.. >>>> >>>> I've since soldered a 15K resistor across the input jack of the >>>> audio >>>> filter, and will do likewise for any other audio filters I >>>> encounter, and use. >>>> >>>> Puzzling, huh? 73 de VE3GFN >>>> ______________________________________________________________ >>>> 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 ______________________________________________________________ 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 wayne burdick
Wayne,
Do you mean the 470 ohm resistors added to the KIO3 Board? If so, both radios had this mod done well before the speaker amps blew. Dave Hachadorian, K6LL Big Bear Lake, California -----Original Message----- From: Wayne Burdick Sent: Tuesday, August 28, 2012 11:18 AM To: Dave Hachadorian Cc: Elecraft Reflector Subject: Re: [Elecraft] K3 speaker audio gone! Dave, Do you have the AF amp current-limiting mod in place? The parts for this mod are installed on the RF board. They've been in production for quite some time, and we can send them to you on request. With the limiter installed, we've seen near-zero problems with the AF amp IC. 73, Wayne N6KR On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: > I have blown the speaker amp twice, in two different radios, by > using a speaker with AGC OFF. POOF! Gone before you can react > by > turning down the audio. > > The factory guys report that they have been unable to duplicate > the problem. Unless you are an EXPERT solderer, replacing the > speaker amp chip is best done by the factory. The job will run > about $125 with shipping, maybe a little less if you ship only > the DSP Board. I don't use the speaker amp any more. I still > think there is a transient susceptibility problem in that > circuitry that they have been unable to find. > > > Dave Hachadorian, K6LL > Big Bear Lake, California > > > > > > > -----Original Message----- > From: Mike Goldstein > Sent: Tuesday, August 28, 2012 9:07 AM > To: [hidden email] > Subject: [Elecraft] K3 speaker audio gone! > > I've lost audio from both the internal speaker in the > K3, > and from the SPKRS output jack on the rear panel. > > At the end of the the first week of using a new NESCAF > audio > filter (which drives my speaker) with the K3, I changed bands, > listened briefly on CW, with the NESCAF filter in the circuit. > I > then changed to SSB, and because the NESCAF filter was adjusted > for a > very narrow audio bandwidth, I decided to switch it out of the > circuit, while the K3 was delivering audio, at a comfortable > listening level.. > > The audio filter was driven from the SPKRS jack on the > back > of the K3, using a stereo plug, with one channel floating. The > SPKRS > jack was CONFIGured as SPKRS = 1. > > A front panel toggle switch on the filter panel turns off the > power > to the NESCAF filter, and re-routes the speaker audio > connection > from > the filter output, to the K3 output directly. I had done this > often, > for the first week of operations. > > This time, however, I briefly saw a "HI CURR" indication on the > front > panel of the K3, and then my speaker audio vanished. > > Unplugging all connections from the rear panel SPKRS jack, and > the > front panel PHONES jack, no longer allows the K3's internal > speaker > to produce audio. Nothing I tried would result in any audio > from > the > external speaker, after connecting that speaker to either of > the > phono jacks that were tied to the rear SPKRS jack, through the > stereo plug. > > The INPUT jack on the SCAF filter (to which the K3's SPKRS jack > was > connected) passes through an isolating capacitor, then a 27K > resistor, before being connected to the chip in the audio > filter. > > Resetting SPRKS = 2, in the CONFIG menu, had no effect on > producing > audio in the external, or internal speaker. > > I still have audio at the PHONES jack on the front panel, so I > can > still use the K3. It subsequently accounted for 380 QSOs in > the > NAQP > CW contest, providing it usual flawless performance. > > I still have audio at the PHONES jack on the rear panel, as > well. > > My theory (and Gary at Elecraft Service agrees it might be the > cause) > is that the audio chip in the K3 didn't like the abrupt change > of > load impedance, from 27K (approx.) to infinity, to 8 ohms, > while > it > was delivering audio.. > > I've since soldered a 15K resistor across the input jack of the > audio > filter, and will do likewise for any other audio filters I > encounter, and use. > > Puzzling, huh? 73 de VE3GFN > ______________________________________________________________ > 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 |
Re: K3 speaker audio gone!
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Wayne, The series resistors do not appear to be documented on the most recent (June 2010) schematic package. At least I can't find any on the front panel board, mainboard, or anywhere on the KIO3. 73, ... Joe, W4TV On 8/28/2012 4:07 PM, Dave Hachadorian wrote: > Wayne, > > Do you mean the 470 ohm resistors added to the KIO3 Board? If > so, both radios had this mod done well before the speaker amps > blew. > > Dave Hachadorian, K6LL > Big Bear Lake, California > > -----Original Message----- > From: Wayne Burdick > Sent: Tuesday, August 28, 2012 11:18 AM > To: Dave Hachadorian > Cc: Elecraft Reflector > Subject: Re: [Elecraft] K3 speaker audio gone! > > Dave, > > Do you have the AF amp current-limiting mod in place? The parts > for > this mod are installed on the RF board. They've been in > production for > quite some time, and we can send them to you on request. > > With the limiter installed, we've seen near-zero problems with > the AF > amp IC. > > 73, > Wayne > N6KR > > > > On Aug 28, 2012, at 10:25 AM, Dave Hachadorian wrote: > >> I have blown the speaker amp twice, in two different radios, by >> using a speaker with AGC OFF. POOF! Gone before you can react >> by >> turning down the audio. >> >> The factory guys report that they have been unable to duplicate >> the problem. Unless you are an EXPERT solderer, replacing the >> speaker amp chip is best done by the factory. The job will run >> about $125 with shipping, maybe a little less if you ship only >> the DSP Board. I don't use the speaker amp any more. I still >> think there is a transient susceptibility problem in that >> circuitry that they have been unable to find. >> >> >> Dave Hachadorian, K6LL >> Big Bear Lake, California >> >> >> >> >> >> >> -----Original Message----- >> From: Mike Goldstein >> Sent: Tuesday, August 28, 2012 9:07 AM >> To: [hidden email] >> Subject: [Elecraft] K3 speaker audio gone! >> >> I've lost audio from both the internal speaker in the >> K3, >> and from the SPKRS output jack on the rear panel. >> >> At the end of the the first week of using a new NESCAF >> audio >> filter (which drives my speaker) with the K3, I changed bands, >> listened briefly on CW, with the NESCAF filter in the circuit. >> I >> then changed to SSB, and because the NESCAF filter was adjusted >> for a >> very narrow audio bandwidth, I decided to switch it out of the >> circuit, while the K3 was delivering audio, at a comfortable >> listening level.. >> >> The audio filter was driven from the SPKRS jack on the >> back >> of the K3, using a stereo plug, with one channel floating. The >> SPKRS >> jack was CONFIGured as SPKRS = 1. >> >> A front panel toggle switch on the filter panel turns off the >> power >> to the NESCAF filter, and re-routes the speaker audio >> connection >> from >> the filter output, to the K3 output directly. I had done this >> often, >> for the first week of operations. >> >> This time, however, I briefly saw a "HI CURR" indication on the >> front >> panel of the K3, and then my speaker audio vanished. >> >> Unplugging all connections from the rear panel SPKRS jack, and >> the >> front panel PHONES jack, no longer allows the K3's internal >> speaker >> to produce audio. Nothing I tried would result in any audio >> from >> the >> external speaker, after connecting that speaker to either of >> the >> phono jacks that were tied to the rear SPKRS jack, through the >> stereo plug. >> >> The INPUT jack on the SCAF filter (to which the K3's SPKRS jack >> was >> connected) passes through an isolating capacitor, then a 27K >> resistor, before being connected to the chip in the audio >> filter. >> >> Resetting SPRKS = 2, in the CONFIG menu, had no effect on >> producing >> audio in the external, or internal speaker. >> >> I still have audio at the PHONES jack on the front panel, so I >> can >> still use the K3. It subsequently accounted for 380 QSOs in >> the >> NAQP >> CW contest, providing it usual flawless performance. >> >> I still have audio at the PHONES jack on the rear panel, as >> well. >> >> My theory (and Gary at Elecraft Service agrees it might be the >> cause) >> is that the audio chip in the K3 didn't like the abrupt change >> of >> load impedance, from 27K (approx.) to infinity, to 8 ohms, >> while >> it >> was delivering audio.. >> >> I've since soldered a 15K resistor across the input jack of the >> audio >> filter, and will do likewise for any other audio filters I >> encounter, and use. >> >> Puzzling, huh? 73 de VE3GFN >> ______________________________________________________________ >> 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 Dave Hachadorian
I have the AF Limit set at 30 and have experienced my share of "crashes" when the AGC is turned off with no damage. (Knocking on wood now!!)
Jim, W4ATK On Aug 28, 2012, at 12:25 PM, "Dave Hachadorian" <[hidden email]> wrote: > I have blown the speaker amp twice, in two different radios, by > using a speaker with AGC OFF. POOF! Gone before you can react by > turning down the audio. > > The factory guys report that they have been unable to duplicate > the problem. Unless you are an EXPERT solderer, replacing the > speaker amp chip is best done by the factory. The job will run > about $125 with shipping, maybe a little less if you ship only > the DSP Board. I don't use the speaker amp any more. I still > think there is a transient susceptibility problem in that > circuitry that they have been unable to find. > > > Dave Hachadorian, K6LL > Big Bear Lake, California > > > > > > > -----Original Message----- > From: Mike Goldstein > Sent: Tuesday, August 28, 2012 9:07 AM > To: [hidden email] > Subject: [Elecraft] K3 speaker audio gone! > > I've lost audio from both the internal speaker in the > K3, > and from the SPKRS output jack on the rear panel. > > At the end of the the first week of using a new NESCAF > audio > filter (which drives my speaker) with the K3, I changed bands, > listened briefly on CW, with the NESCAF filter in the circuit. I > then changed to SSB, and because the NESCAF filter was adjusted > for a > very narrow audio bandwidth, I decided to switch it out of the > circuit, while the K3 was delivering audio, at a comfortable > listening level.. > > The audio filter was driven from the SPKRS jack on the > back > of the K3, using a stereo plug, with one channel floating. The > SPKRS > jack was CONFIGured as SPKRS = 1. > > A front panel toggle switch on the filter panel turns off the > power > to the NESCAF filter, and re-routes the speaker audio connection > from > the filter output, to the K3 output directly. I had done this > often, > for the first week of operations. > > This time, however, I briefly saw a "HI CURR" indication on the > front > panel of the K3, and then my speaker audio vanished. > > Unplugging all connections from the rear panel SPKRS jack, and > the > front panel PHONES jack, no longer allows the K3's internal > speaker > to produce audio. Nothing I tried would result in any audio from > the > external speaker, after connecting that speaker to either of the > phono jacks that were tied to the rear SPKRS jack, through the > stereo plug. > > The INPUT jack on the SCAF filter (to which the K3's SPKRS jack > was > connected) passes through an isolating capacitor, then a 27K > resistor, before being connected to the chip in the audio filter. > > Resetting SPRKS = 2, in the CONFIG menu, had no effect on > producing > audio in the external, or internal speaker. > > I still have audio at the PHONES jack on the front panel, so I > can > still use the K3. It subsequently accounted for 380 QSOs in the > NAQP > CW contest, providing it usual flawless performance. > > I still have audio at the PHONES jack on the rear panel, as well. > > My theory (and Gary at Elecraft Service agrees it might be the > cause) > is that the audio chip in the K3 didn't like the abrupt change of > load impedance, from 27K (approx.) to infinity, to 8 ohms, while > it > was delivering audio.. > > I've since soldered a 15K resistor across the input jack of the > audio > filter, and will do likewise for any other audio filters I > encounter, and use. > > Puzzling, huh? 73 de VE3GFN > ______________________________________________________________ > 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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