What's the purpose of these copper coils with resitors inside them in A Yamaha RX-V396RDS amplifier?












4












$begingroup$


Picture of two copper coils from PCB Main 1 of a Yamaha RX-V396RDS



This is an bit of an overly specific question, but I'm curious about the purpose of these coils inside a Yamaha RX-V396RDS amplifier and wondered if anyone could explain what they're for. They appear on PCB Main 1. Also, would having the realtor inside the coil touching the inside of the coil be likely to cause a channel to not work?



Background to the question: the front right output of the amp has been behaving a littler weirdly for a while, mostly being slightly quieter and less clear than the left, but I've lived with it. This evening I noticed that it had completely cut out, so went delving inside the amp to see if I could spot any loose connections or burnt out components. Nothing looked obviously out of place or broken, but I noticed that on one of the large boards connected to the output board the resistor in one of the copper coils was touching the inside of the coil. I'm no expert, but I assumed that having two components directly touching like that probably wasn't ideal, so I carefully moved it to be more central. Having done that I thought I'd test it out and was surprised to find that the front right speaker was back. I tried to google to find an answer and looked at the schematics, but have no idea of what I did actually fixed things, or if unplugging the amp for the first time in a while may have reset something that had tripped or otherwise gone wonky.










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New contributor




andyface is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • 1




    $begingroup$
    If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
    $endgroup$
    – TimWescott
    5 hours ago






  • 1




    $begingroup$
    My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
    $endgroup$
    – Elliot Alderson
    4 hours ago










  • $begingroup$
    Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
    $endgroup$
    – analogsystemsrf
    4 hours ago
















4












$begingroup$


Picture of two copper coils from PCB Main 1 of a Yamaha RX-V396RDS



This is an bit of an overly specific question, but I'm curious about the purpose of these coils inside a Yamaha RX-V396RDS amplifier and wondered if anyone could explain what they're for. They appear on PCB Main 1. Also, would having the realtor inside the coil touching the inside of the coil be likely to cause a channel to not work?



Background to the question: the front right output of the amp has been behaving a littler weirdly for a while, mostly being slightly quieter and less clear than the left, but I've lived with it. This evening I noticed that it had completely cut out, so went delving inside the amp to see if I could spot any loose connections or burnt out components. Nothing looked obviously out of place or broken, but I noticed that on one of the large boards connected to the output board the resistor in one of the copper coils was touching the inside of the coil. I'm no expert, but I assumed that having two components directly touching like that probably wasn't ideal, so I carefully moved it to be more central. Having done that I thought I'd test it out and was surprised to find that the front right speaker was back. I tried to google to find an answer and looked at the schematics, but have no idea of what I did actually fixed things, or if unplugging the amp for the first time in a while may have reset something that had tripped or otherwise gone wonky.










share|improve this question









New contributor




andyface is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 1




    $begingroup$
    If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
    $endgroup$
    – TimWescott
    5 hours ago






  • 1




    $begingroup$
    My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
    $endgroup$
    – Elliot Alderson
    4 hours ago










  • $begingroup$
    Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
    $endgroup$
    – analogsystemsrf
    4 hours ago














4












4








4





$begingroup$


Picture of two copper coils from PCB Main 1 of a Yamaha RX-V396RDS



This is an bit of an overly specific question, but I'm curious about the purpose of these coils inside a Yamaha RX-V396RDS amplifier and wondered if anyone could explain what they're for. They appear on PCB Main 1. Also, would having the realtor inside the coil touching the inside of the coil be likely to cause a channel to not work?



Background to the question: the front right output of the amp has been behaving a littler weirdly for a while, mostly being slightly quieter and less clear than the left, but I've lived with it. This evening I noticed that it had completely cut out, so went delving inside the amp to see if I could spot any loose connections or burnt out components. Nothing looked obviously out of place or broken, but I noticed that on one of the large boards connected to the output board the resistor in one of the copper coils was touching the inside of the coil. I'm no expert, but I assumed that having two components directly touching like that probably wasn't ideal, so I carefully moved it to be more central. Having done that I thought I'd test it out and was surprised to find that the front right speaker was back. I tried to google to find an answer and looked at the schematics, but have no idea of what I did actually fixed things, or if unplugging the amp for the first time in a while may have reset something that had tripped or otherwise gone wonky.










share|improve this question









New contributor




andyface is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




Picture of two copper coils from PCB Main 1 of a Yamaha RX-V396RDS



This is an bit of an overly specific question, but I'm curious about the purpose of these coils inside a Yamaha RX-V396RDS amplifier and wondered if anyone could explain what they're for. They appear on PCB Main 1. Also, would having the realtor inside the coil touching the inside of the coil be likely to cause a channel to not work?



Background to the question: the front right output of the amp has been behaving a littler weirdly for a while, mostly being slightly quieter and less clear than the left, but I've lived with it. This evening I noticed that it had completely cut out, so went delving inside the amp to see if I could spot any loose connections or burnt out components. Nothing looked obviously out of place or broken, but I noticed that on one of the large boards connected to the output board the resistor in one of the copper coils was touching the inside of the coil. I'm no expert, but I assumed that having two components directly touching like that probably wasn't ideal, so I carefully moved it to be more central. Having done that I thought I'd test it out and was surprised to find that the front right speaker was back. I tried to google to find an answer and looked at the schematics, but have no idea of what I did actually fixed things, or if unplugging the amp for the first time in a while may have reset something that had tripped or otherwise gone wonky.







pcb amplifier resistors short-circuit






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edited 2 hours ago







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asked 5 hours ago









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andyface is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






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Check out our Code of Conduct.








  • 1




    $begingroup$
    If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
    $endgroup$
    – TimWescott
    5 hours ago






  • 1




    $begingroup$
    My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
    $endgroup$
    – Elliot Alderson
    4 hours ago










  • $begingroup$
    Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
    $endgroup$
    – analogsystemsrf
    4 hours ago














  • 1




    $begingroup$
    If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
    $endgroup$
    – TimWescott
    5 hours ago






  • 1




    $begingroup$
    My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
    $endgroup$
    – Elliot Alderson
    4 hours ago










  • $begingroup$
    Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
    $endgroup$
    – analogsystemsrf
    4 hours ago








1




1




$begingroup$
If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
$endgroup$
– TimWescott
5 hours ago




$begingroup$
If the coil turns touch then the coil is made of enameled wire, and having a resistor lead touch it shouldn't make much difference. Whatever the function of that coil is, it doesn't do much at all at audio frequencies. if it's not there for some sort of cable equalization on the digital signals coming in, I have no clue.
$endgroup$
– TimWescott
5 hours ago




1




1




$begingroup$
My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
$endgroup$
– Elliot Alderson
4 hours ago




$begingroup$
My guess is that they serve some important purpose for the sales and marketing department at Yamaha. They would work even better if they had LEDs inside them for illumination.
$endgroup$
– Elliot Alderson
4 hours ago












$begingroup$
Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
$endgroup$
– analogsystemsrf
4 hours ago




$begingroup$
Not a lot of inductance there, but could be to slow down the rectifier surge currents in the power supplies. If you have +-40 volt supplies, from a full wave rectifier, you'd need two. Fast current surges are bad interferers. And copper foil does not shield low-frequency magnetic fields.
$endgroup$
– analogsystemsrf
4 hours ago










1 Answer
1






active

oldest

votes


















4












$begingroup$

The coil can be found in service manual schematics. It is an RL filter to isolate the amplifier output circuitry from the speaker terminals.






share|improve this answer









$endgroup$













  • $begingroup$
    So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
    $endgroup$
    – Toor
    4 hours ago












  • $begingroup$
    So when "shorted", that channel was oscillating?
    $endgroup$
    – analogsystemsrf
    4 hours ago










  • $begingroup$
    ..some PCB designer somewhere is loving this attention.
    $endgroup$
    – Tyler Stone
    4 hours ago










  • $begingroup$
    They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
    $endgroup$
    – james
    3 hours ago










  • $begingroup$
    Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
    $endgroup$
    – andyface
    2 hours ago











Your Answer





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1 Answer
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active

oldest

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1 Answer
1






active

oldest

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active

oldest

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active

oldest

votes









4












$begingroup$

The coil can be found in service manual schematics. It is an RL filter to isolate the amplifier output circuitry from the speaker terminals.






share|improve this answer









$endgroup$













  • $begingroup$
    So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
    $endgroup$
    – Toor
    4 hours ago












  • $begingroup$
    So when "shorted", that channel was oscillating?
    $endgroup$
    – analogsystemsrf
    4 hours ago










  • $begingroup$
    ..some PCB designer somewhere is loving this attention.
    $endgroup$
    – Tyler Stone
    4 hours ago










  • $begingroup$
    They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
    $endgroup$
    – james
    3 hours ago










  • $begingroup$
    Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
    $endgroup$
    – andyface
    2 hours ago
















4












$begingroup$

The coil can be found in service manual schematics. It is an RL filter to isolate the amplifier output circuitry from the speaker terminals.






share|improve this answer









$endgroup$













  • $begingroup$
    So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
    $endgroup$
    – Toor
    4 hours ago












  • $begingroup$
    So when "shorted", that channel was oscillating?
    $endgroup$
    – analogsystemsrf
    4 hours ago










  • $begingroup$
    ..some PCB designer somewhere is loving this attention.
    $endgroup$
    – Tyler Stone
    4 hours ago










  • $begingroup$
    They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
    $endgroup$
    – james
    3 hours ago










  • $begingroup$
    Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
    $endgroup$
    – andyface
    2 hours ago














4












4








4





$begingroup$

The coil can be found in service manual schematics. It is an RL filter to isolate the amplifier output circuitry from the speaker terminals.






share|improve this answer









$endgroup$



The coil can be found in service manual schematics. It is an RL filter to isolate the amplifier output circuitry from the speaker terminals.







share|improve this answer












share|improve this answer



share|improve this answer










answered 4 hours ago









JustmeJustme

1,6181310




1,6181310












  • $begingroup$
    So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
    $endgroup$
    – Toor
    4 hours ago












  • $begingroup$
    So when "shorted", that channel was oscillating?
    $endgroup$
    – analogsystemsrf
    4 hours ago










  • $begingroup$
    ..some PCB designer somewhere is loving this attention.
    $endgroup$
    – Tyler Stone
    4 hours ago










  • $begingroup$
    They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
    $endgroup$
    – james
    3 hours ago










  • $begingroup$
    Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
    $endgroup$
    – andyface
    2 hours ago


















  • $begingroup$
    So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
    $endgroup$
    – Toor
    4 hours ago












  • $begingroup$
    So when "shorted", that channel was oscillating?
    $endgroup$
    – analogsystemsrf
    4 hours ago










  • $begingroup$
    ..some PCB designer somewhere is loving this attention.
    $endgroup$
    – Tyler Stone
    4 hours ago










  • $begingroup$
    They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
    $endgroup$
    – james
    3 hours ago










  • $begingroup$
    Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
    $endgroup$
    – andyface
    2 hours ago
















$begingroup$
So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
$endgroup$
– Toor
4 hours ago






$begingroup$
So it's just a space saving measure to put the resistor in the middle? or does that do something else too because there looks to be plenty of PCB space.
$endgroup$
– Toor
4 hours ago














$begingroup$
So when "shorted", that channel was oscillating?
$endgroup$
– analogsystemsrf
4 hours ago




$begingroup$
So when "shorted", that channel was oscillating?
$endgroup$
– analogsystemsrf
4 hours ago












$begingroup$
..some PCB designer somewhere is loving this attention.
$endgroup$
– Tyler Stone
4 hours ago




$begingroup$
..some PCB designer somewhere is loving this attention.
$endgroup$
– Tyler Stone
4 hours ago












$begingroup$
They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
$endgroup$
– james
3 hours ago




$begingroup$
They're listed as 1uH coils, and with a quick look at the schematic in the service manual, appear to be there to add stability to the output stage.
$endgroup$
– james
3 hours ago












$begingroup$
Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
$endgroup$
– andyface
2 hours ago




$begingroup$
Ahh interesting. The schematics I found didn't seem to give too much details. Would the resistor in the centre touching the inside of the coil cause a channel to not work properly?
$endgroup$
– andyface
2 hours ago










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