Harman Kardon AVR210, no audio. Fixed.
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From: David Farber on 24 May 2010 19:17 Mark Zacharias wrote: > "David Farber" <farberbear.unspam(a)aol.com> wrote in message > news:4bbba75a$0$27750$bd467cd0(a)news.dslextreme.com... >> 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 >> > > Don't know if this is accurate info but B & D Enterprises (bdent.com) > website says they'll have it in 2 weeks. > > Their phone number is 800-458-6053. > > Mark Z. Hi Mark, I ordered the part through B&D. It took about 6 weeks to get the part from Japan. It came in an original Sony package. I wonder how it's discontinued in the US but not in Japan? I installed the new part and smelled a faint cooking odor. I noticed that the color of the bands of R485 looked faded (see page 123 of the manual). It's a 4.7 ohm 2 watt resistor that measured closer to 8 ohms. Then I noticed there was a 1.2 ohm load to ground off of the +5 volt regulator, IC485. I traced that down to a nearly shorted optical 3 input (page 124). That board is buried in the front panel and a pain to get to. I just pulled the connector to the board at its other end and the short disappeared. When I powered it up again, there was audio but with a background hum. I checked the output of IC 485 and there was noticeable 60Hz noise. Back upstream I found C487, 6,800uF @16V, a bit bulging with an esr of about 1 ohm. I replaced that and all is good now. Thanks for your reply. -- David Farber David Farber's Service Center L.A., CA
From: Mark Zacharias on 25 May 2010 06:14 "David Farber" <farberbear.unspam(a)aol.com> wrote in message news:4bfb0915$0$27749$bd467cd0(a)news.dslextreme.com... > Mark Zacharias wrote: >> "David Farber" <farberbear.unspam(a)aol.com> wrote in message >> news:4bbba75a$0$27750$bd467cd0(a)news.dslextreme.com... >>> 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 >>> >> >> Don't know if this is accurate info but B & D Enterprises (bdent.com) >> website says they'll have it in 2 weeks. >> >> Their phone number is 800-458-6053. >> >> Mark Z. > > Hi Mark, > > I ordered the part through B&D. It took about 6 weeks to get the part from > Japan. It came in an original Sony package. I wonder how it's discontinued > in the US but not in Japan? > > I installed the new part and smelled a faint cooking odor. I noticed that > the color of the bands of R485 looked faded (see page 123 of the manual). > It's a 4.7 ohm 2 watt resistor that measured closer to 8 ohms. Then I > noticed there was a 1.2 ohm load to ground off of the +5 volt regulator, > IC485. I traced that down to a nearly shorted optical 3 input (page 124). > That board is buried in the front panel and a pain to get to. I just > pulled the connector to the board at its other end and the short > disappeared. > > When I powered it up again, there was audio but with a background hum. I > checked the output of IC 485 and there was noticeable 60Hz noise. Back > upstream I found C487, 6,800uF @16V, a bit bulging with an esr of about 1 > ohm. I replaced that and all is good now. > > Thanks for your reply. > -- > David Farber > David Farber's Service Center > L.A., CA > Thanks much for the update. Very often we don't get "the rest of the story". Mark Z.
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