Harman Kardon AVR210, no audio.
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From: David Farber on 1 Apr 2010 18:12 This Harman Kardon AVR210 receiver has no audio output in any mode. Customer said it just went out all of a sudden. I was able to find a copy of the service manual here: http://eserviceinfo.com/downloadsm/46799/Harman/Kardon_AVR210.html It's in four parts and you'll need a utility that can unpack a rar file to see it. The manual is 135 pages so when referring to it, I've included the page numbers. I performed the part modification as suggested on page 19. It didn't correct the problem. Then I traced signal as shown in the chart on pages 25-26. Using the direct input, I was able to get audio out of the tape output jacks. There is no output from the preamp output jacks. There is no protection relay that I can see and there is no dc offset at the power amplifier output. Referring to the signal flow chart on page 26, the audio input signal is present on pins 4 and 25 of IC 706 (electronic volume control) but missing on pins 3 and 26 of IC 706. The schematic of this circuit is on page 116. However when I rotate the volume control, the audio will appear as long as the knob is moving. As soon as the control is left alone, the audio mutes. The output pins are 3 and 26, of IC 706. The signal appears to be clean though I estimate the speaker output to be about 30dB less than where it's supposed to be while it is present. If I bridge the input to the output pins of IC706, an attenuated signal appears but it's too low for any output to register at the speakers. Now, referring to the block diagram on page 30, you'll notice IC 716 and the muting transistor(s) that follows. Back to page 116, there seems to be enough forward bias on Q716 and Q717 .(676 volts) to possibly mute the output if there were any input to amplify. So in light of all these observations, do I just replace IC706? It's about $30 but I'm wondering if there's some muting going on behind the scenes that can be contributing to this problem. Thanks for your reply. -- David Farber David Farber's Service Center L.A., CA
From: Mark Zacharias on 3 Apr 2010 06:44 "David Farber" <farberbear.unspam(a)aol.com> wrote in message news:4bb51a34$0$27759$bd467cd0(a)news.dslextreme.com... > This Harman Kardon AVR210 receiver has no audio output in any mode. > Customer > said it just went out all of a sudden. I was able to find a copy of the > service manual here: > http://eserviceinfo.com/downloadsm/46799/Harman/Kardon_AVR210.html It's in > four parts and you'll need a utility that can unpack a rar file to see it. > The manual is 135 pages so when referring to it, I've included the page > numbers. > > I performed the part modification as suggested on page 19. It didn't > correct > the problem. > > Then I traced signal as shown in the chart on pages 25-26. Using the > direct > input, I was able to get audio out of the tape output jacks. There is no > output from the preamp output jacks. There is no protection relay that I > can > see and there is no dc offset at the power amplifier output. > > Referring to the signal flow chart on page 26, the audio input signal is > present on pins 4 and 25 of IC 706 (electronic volume control) but missing > on pins 3 and 26 of IC 706. The schematic of this circuit is on page 116. > However when I rotate the volume control, the audio will appear as long as > the knob is moving. As soon as the control is left alone, the audio mutes. > The output pins are 3 and 26, of IC 706. The signal appears to be clean > though I estimate the speaker output to be about 30dB less than where it's > supposed to be while it is present. If I bridge the input to the output > pins > of IC706, an attenuated signal appears but it's too low for any output to > register at the speakers. > > Now, referring to the block diagram on page 30, you'll notice IC 716 and > the > muting transistor(s) that follows. Back to page 116, there seems to be > enough forward bias on Q716 and Q717 .(676 volts) to possibly mute the > output if there were any input to amplify. > > So in light of all these observations, do I just replace IC706? It's about > $30 but I'm wondering if there's some muting going on behind the scenes > that > can be contributing to this problem. > > Thanks for your reply. > -- > David Farber > David Farber's Service Center > L.A., CA > > > The .676 at the base of the muting transistors is certainly enough to be considered a symptom. You've tried a reset, yes? If the receiver had been told at some point that no speakers were connected, then all channels might just be muted. Which brings the question, does the headphone jack work? Many modern receivers include a switch in the headphones jack specifically to mute the speakers as soon as the headphones are plugged in. In typical HK fashion, there does not appear to be any speaker relays in this thing, not with a quick glance at page 121 anyway, so if you have not already looked in that area it might not be a bad idea... You could look at the junction of R854 and R855 to check the mute drive which I suspect is active, or just short B-E on one of the muting transistors... Of course there could be an actual circuit malfunction, and if this is confirmed to be the case, frankly without LOTS of patience and a willingness to lose money on the repair, and lacking boards to swap to narrow it down, I would be tempted to just pull the plug on this one. Of course this assumes you have eliminated the usual suspects - the various power supplies, and so forth. A sign of old age I suppose, but I'm less and less willing to break a sweat on these. The lack of serviceability on the vast majority of late model receivers is almost criminal. The manufacturers don't care that they are difficult to assemble, since they are using cheap Chinese labor anyway, they don't care that it's tough on the warranty servicers, and they certainly don't want them fixed out of warranty. The trend has always been there of course but it's really got much worse the past 10-20 years. Mark Z.
From: David Farber on 3 Apr 2010 22:33 Mark Zacharias wrote: > "David Farber" <farberbear.unspam(a)aol.com> wrote in message > news:4bb51a34$0$27759$bd467cd0(a)news.dslextreme.com... >> This Harman Kardon AVR210 receiver has no audio output in any mode. >> Customer >> said it just went out all of a sudden. I was able to find a copy of >> the service manual here: >> http://eserviceinfo.com/downloadsm/46799/Harman/Kardon_AVR210.html >> It's in four parts and you'll need a utility that can unpack a rar >> file to see it. The manual is 135 pages so when referring to it, >> I've included the page numbers. >> >> I performed the part modification as suggested on page 19. It didn't >> correct >> the problem. >> >> Then I traced signal as shown in the chart on pages 25-26. Using the >> direct >> input, I was able to get audio out of the tape output jacks. There >> is no output from the preamp output jacks. There is no protection >> relay that I can >> see and there is no dc offset at the power amplifier output. >> >> Referring to the signal flow chart on page 26, the audio input >> signal is present on pins 4 and 25 of IC 706 (electronic volume >> control) but missing on pins 3 and 26 of IC 706. The schematic of >> this circuit is on page 116. However when I rotate the volume >> control, the audio will appear as long as the knob is moving. As >> soon as the control is left alone, the audio mutes. The output pins >> are 3 and 26, of IC 706. The signal appears to be clean though I >> estimate the speaker output to be about 30dB less than where it's >> supposed to be while it is present. If I bridge the input to the >> output pins of IC706, an attenuated signal appears but it's too low for >> any >> output to register at the speakers. >> >> Now, referring to the block diagram on page 30, you'll notice IC 716 >> and the >> muting transistor(s) that follows. Back to page 116, there seems to >> be enough forward bias on Q716 and Q717 .(676 volts) to possibly >> mute the output if there were any input to amplify. >> >> So in light of all these observations, do I just replace IC706? It's >> about $30 but I'm wondering if there's some muting going on behind >> the scenes that >> can be contributing to this problem. >> >> Thanks for your reply. >> -- >> David Farber >> David Farber's Service Center >> L.A., CA >> >> >> > > The .676 at the base of the muting transistors is certainly enough to > be considered a symptom. You've tried a reset, yes? If the receiver > had been told at some point that no speakers were connected, then all > channels might just be muted. Which brings the question, does the > headphone jack work? Many modern receivers include a switch in the > headphones jack specifically to mute the speakers as soon as the > headphones are plugged in. In typical HK fashion, there does not > appear to be any speaker relays in this thing, not with a quick > glance at page 121 anyway, so if you have not already looked in that > area it might not be a bad idea... You could look at the junction of R854 > and R855 to check the mute > drive which I suspect is active, or just short B-E on one of the > muting transistors... > Of course there could be an actual circuit malfunction, and if this is > confirmed to be the case, frankly without LOTS of patience and a > willingness to lose money on the repair, and lacking boards to swap > to narrow it down, I would be tempted to just pull the plug on this > one. Of course this assumes you have eliminated the usual suspects - the > various power supplies, and so forth. > > A sign of old age I suppose, but I'm less and less willing to break a > sweat on these. The lack of serviceability on the vast majority of > late model receivers is almost criminal. The manufacturers don't care > that they are difficult to assemble, since they are using cheap > Chinese labor anyway, they don't care that it's tough on the warranty > servicers, and they certainly don't want them fixed out of warranty. > The trend has always been there of course but it's really got much > worse the past 10-20 years. > Mark Z. Hi Mark, The mute drive at the junction of R854 and R855 is about 3.5 volts iirc. I temporarily did short the mute transistor but I still didn't see signal. Again, there is not much signal coming out of IC706 to begin with. I looked at the headphone circuit and noticed there is a switch in the jack that goes directly back to the uP, pin 16 of IC201 on page 119, labeled H/P _IN. I assume this either mutes the speakers or puts the receiver in two channel mode. But even if the muting was enabled in error, it still wouldn't explain why there's no signal passing through IC 706, the electronic volume control. You would still need to be able to adjust the volume when using the headphones. This would be much easier if this model had pre-amp out, main in jumpers. But it doesn't. I'm leaning toward replacing IC706. Thanks for your reply. -- David Farber David Farber's Service Center L.A., CA
From: Mark Zacharias on 4 Apr 2010 08:43 "David Farber" <farberbear.unspam(a)aol.com> wrote in message news:4bb7fa57$0$16970$bd467cd0(a)news.dslextreme.com... > Mark Zacharias wrote: >> "David Farber" <farberbear.unspam(a)aol.com> wrote in message >> news:4bb51a34$0$27759$bd467cd0(a)news.dslextreme.com... >>> This Harman Kardon AVR210 receiver has no audio output in any mode. >>> Customer >>> said it just went out all of a sudden. I was able to find a copy of >>> the service manual here: >>> http://eserviceinfo.com/downloadsm/46799/Harman/Kardon_AVR210.html >>> It's in four parts and you'll need a utility that can unpack a rar >>> file to see it. The manual is 135 pages so when referring to it, >>> I've included the page numbers. >>> >>> I performed the part modification as suggested on page 19. It didn't >>> correct >>> the problem. >>> >>> Then I traced signal as shown in the chart on pages 25-26. Using the >>> direct >>> input, I was able to get audio out of the tape output jacks. There >>> is no output from the preamp output jacks. There is no protection >>> relay that I can >>> see and there is no dc offset at the power amplifier output. >>> >>> Referring to the signal flow chart on page 26, the audio input >>> signal is present on pins 4 and 25 of IC 706 (electronic volume >>> control) but missing on pins 3 and 26 of IC 706. The schematic of >>> this circuit is on page 116. However when I rotate the volume >>> control, the audio will appear as long as the knob is moving. As >>> soon as the control is left alone, the audio mutes. The output pins >>> are 3 and 26, of IC 706. The signal appears to be clean though I >>> estimate the speaker output to be about 30dB less than where it's >>> supposed to be while it is present. If I bridge the input to the >>> output pins of IC706, an attenuated signal appears but it's too low for >>> any >>> output to register at the speakers. >>> >>> Now, referring to the block diagram on page 30, you'll notice IC 716 >>> and the >>> muting transistor(s) that follows. Back to page 116, there seems to >>> be enough forward bias on Q716 and Q717 .(676 volts) to possibly >>> mute the output if there were any input to amplify. >>> >>> So in light of all these observations, do I just replace IC706? It's >>> about $30 but I'm wondering if there's some muting going on behind >>> the scenes that >>> can be contributing to this problem. >>> >>> Thanks for your reply. >>> -- >>> David Farber >>> David Farber's Service Center >>> L.A., CA >>> >>> >>> >> >> The .676 at the base of the muting transistors is certainly enough to >> be considered a symptom. You've tried a reset, yes? If the receiver >> had been told at some point that no speakers were connected, then all >> channels might just be muted. Which brings the question, does the >> headphone jack work? Many modern receivers include a switch in the >> headphones jack specifically to mute the speakers as soon as the >> headphones are plugged in. In typical HK fashion, there does not >> appear to be any speaker relays in this thing, not with a quick >> glance at page 121 anyway, so if you have not already looked in that >> area it might not be a bad idea... You could look at the junction of R854 >> and R855 to check the mute >> drive which I suspect is active, or just short B-E on one of the >> muting transistors... >> Of course there could be an actual circuit malfunction, and if this is >> confirmed to be the case, frankly without LOTS of patience and a >> willingness to lose money on the repair, and lacking boards to swap >> to narrow it down, I would be tempted to just pull the plug on this >> one. Of course this assumes you have eliminated the usual suspects - the >> various power supplies, and so forth. >> >> A sign of old age I suppose, but I'm less and less willing to break a >> sweat on these. The lack of serviceability on the vast majority of >> late model receivers is almost criminal. The manufacturers don't care >> that they are difficult to assemble, since they are using cheap >> Chinese labor anyway, they don't care that it's tough on the warranty >> servicers, and they certainly don't want them fixed out of warranty. >> The trend has always been there of course but it's really got much >> worse the past 10-20 years. >> Mark Z. > > Hi Mark, > > The mute drive at the junction of R854 and R855 is about 3.5 volts iirc. I > temporarily did short the mute transistor but I still didn't see signal. > Again, there is not much signal coming out of IC706 to begin with. > > I looked at the headphone circuit and noticed there is a switch in the > jack > that goes directly back to the uP, pin 16 of IC201 on page 119, labeled > H/P > _IN. I assume this either mutes the speakers or puts the receiver in two > channel mode. But even if the muting was enabled in error, it still > wouldn't > explain why there's no signal passing through IC 706, the electronic > volume > control. You would still need to be able to adjust the volume when using > the > headphones. > > This would be much easier if this model had pre-amp out, main in jumpers. > But it doesn't. > > I'm leaning toward replacing IC706. > > Thanks for your reply. > -- > David Farber > David Farber's Service Center > L.A., CA > > > >But even if the muting was enabled in error, it still wouldn't > explain why there's no signal passing through IC 706, the electronic > volume > control. Duh... I'd forgotten that... sorry. I do think I'd look at any Data, Clock, and Chip Enable lines going to that chip and see if they are active when they are supposed to. I had one just the other day where the CE line was leaky right through the chip, 450 ohms to ground. They don't work so good that way... Mark Z.
From: David Farber on 6 Apr 2010 17:27
Mark Zacharias wrote: > "David Farber" <farberbear.unspam(a)aol.com> wrote in message > news:4bb7fa57$0$16970$bd467cd0(a)news.dslextreme.com... >> Mark Zacharias wrote: >>> "David Farber" <farberbear.unspam(a)aol.com> wrote in message >>> news:4bb51a34$0$27759$bd467cd0(a)news.dslextreme.com... >>>> This Harman Kardon AVR210 receiver has no audio output in any mode. >>>> Customer >>>> said it just went out all of a sudden. I was able to find a copy of >>>> the service manual here: >>>> http://eserviceinfo.com/downloadsm/46799/Harman/Kardon_AVR210.html >>>> It's in four parts and you'll need a utility that can unpack a rar >>>> file to see it. The manual is 135 pages so when referring to it, >>>> I've included the page numbers. >>>> >>>> I performed the part modification as suggested on page 19. It >>>> didn't correct >>>> the problem. >>>> >>>> Then I traced signal as shown in the chart on pages 25-26. Using >>>> the direct >>>> input, I was able to get audio out of the tape output jacks. There >>>> is no output from the preamp output jacks. There is no protection >>>> relay that I can >>>> see and there is no dc offset at the power amplifier output. >>>> >>>> Referring to the signal flow chart on page 26, the audio input >>>> signal is present on pins 4 and 25 of IC 706 (electronic volume >>>> control) but missing on pins 3 and 26 of IC 706. The schematic of >>>> this circuit is on page 116. However when I rotate the volume >>>> control, the audio will appear as long as the knob is moving. As >>>> soon as the control is left alone, the audio mutes. The output pins >>>> are 3 and 26, of IC 706. The signal appears to be clean though I >>>> estimate the speaker output to be about 30dB less than where it's >>>> supposed to be while it is present. If I bridge the input to the >>>> output pins of IC706, an attenuated signal appears but it's too >>>> low for any >>>> output to register at the speakers. >>>> >>>> Now, referring to the block diagram on page 30, you'll notice IC >>>> 716 and the >>>> muting transistor(s) that follows. Back to page 116, there seems to >>>> be enough forward bias on Q716 and Q717 .(676 volts) to possibly >>>> mute the output if there were any input to amplify. >>>> >>>> So in light of all these observations, do I just replace IC706? >>>> It's about $30 but I'm wondering if there's some muting going on >>>> behind the scenes that >>>> can be contributing to this problem. >>>> >>>> Thanks for your reply. >>>> -- >>>> David Farber >>>> David Farber's Service Center >>>> L.A., CA >>>> >>>> >>>> >>> >>> The .676 at the base of the muting transistors is certainly enough >>> to be considered a symptom. You've tried a reset, yes? If the receiver >>> had been told at some point that no speakers were connected, then >>> all channels might just be muted. Which brings the question, does >>> the headphone jack work? Many modern receivers include a switch in >>> the headphones jack specifically to mute the speakers as soon as the >>> headphones are plugged in. In typical HK fashion, there does not >>> appear to be any speaker relays in this thing, not with a quick >>> glance at page 121 anyway, so if you have not already looked in that >>> area it might not be a bad idea... You could look at the junction >>> of R854 and R855 to check the mute >>> drive which I suspect is active, or just short B-E on one of the >>> muting transistors... >>> Of course there could be an actual circuit malfunction, and if this >>> is confirmed to be the case, frankly without LOTS of patience and a >>> willingness to lose money on the repair, and lacking boards to swap >>> to narrow it down, I would be tempted to just pull the plug on this >>> one. Of course this assumes you have eliminated the usual suspects >>> - the various power supplies, and so forth. >>> >>> A sign of old age I suppose, but I'm less and less willing to break >>> a sweat on these. The lack of serviceability on the vast majority of >>> late model receivers is almost criminal. The manufacturers don't >>> care that they are difficult to assemble, since they are using cheap >>> Chinese labor anyway, they don't care that it's tough on the >>> warranty servicers, and they certainly don't want them fixed out of >>> warranty. The trend has always been there of course but it's really got >>> much >>> worse the past 10-20 years. >>> Mark Z. >> >> Hi Mark, >> >> The mute drive at the junction of R854 and R855 is about 3.5 volts >> iirc. I temporarily did short the mute transistor but I still didn't >> see signal. Again, there is not much signal coming out of IC706 to >> begin with. I looked at the headphone circuit and noticed there is a >> switch in >> the jack >> that goes directly back to the uP, pin 16 of IC201 on page 119, >> labeled H/P >> _IN. I assume this either mutes the speakers or puts the receiver >> in two channel mode. But even if the muting was enabled in error, it >> still wouldn't >> explain why there's no signal passing through IC 706, the electronic >> volume >> control. You would still need to be able to adjust the volume when >> using the >> headphones. >> >> This would be much easier if this model had pre-amp out, main in >> jumpers. But it doesn't. >> >> I'm leaning toward replacing IC706. >> >> Thanks for your reply. >> -- >> David Farber >> David Farber's Service Center >> L.A., CA >> >> >> > > > >> But even if the muting was enabled in error, it still wouldn't >> explain why there's no signal passing through IC 706, the electronic >> volume >> control. > > Duh... I'd forgotten that... sorry. > > I do think I'd look at any Data, Clock, and Chip Enable lines going > to that chip and see if they are active when they are supposed to. I > had one just the other day where the CE line was leaky right through > the chip, 450 ohms to ground. They don't work so good that way... > > Mark Z. Hi Mark, It appears this is all moot now because the TC9482F volume control IC is no longer available from Harman or Sony. Anyone have one sitting on a shelf somewhere? Thanks for your reply. -- David Farber David Farber's Service Center L.A., CA |