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Discussion Starter · #1 ·
I normally keep the volume down. This time I just wanted to show it to someone and I raised the volume. It wasn't even that high; as I was raising the volume, at some point the receiver flashes and shuts down. I turn it on and it signals 'check speaker wires' and then shuts down again. I try a few more times and the same message and result even when I disconnect all speaker wires. I then smell a burnt thing from the receiver. It looks like something burnt inside.


My receiver is Onkyo TX-NR809 but I doubt it has much to do with this speaker. It looks like something is wrong with my wires.speakers. But what can it be? I hear about a possible short on the wires. I check all wires and speakers with my multi-meter and they are seem alright (no short). I however noticed something. The center channel speaker in my system has been of a different brand and model than the rest since it was sent as a replacement for my broken center channel speaker (under warranty coverage). I noticed while all other speakers are 8 ohm, this one is a 4ohm speaker! Can this be the reason behind what has happened? My speaker brand is Theater Research which is not a well known brand either. But other than the resistance, what else can I check to make sure the speakers and wiring are functioning fine? Or, should I just replace them all?


The receiver is out for repair but I would like to make sure this won't happen again once it's back.
 

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Hard to say.


Could have been a fault within the receiver, or something with the connections, or one of the speakers.


Problem is, now that it's all disconnected, you may never know for sure. At this point I'd check the loop resistance of the speaker wires+speakers at the point of amplfier connection. 'Bout all you can do at this point.
 

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Try hooking up the speakers on at a time and turning the volume up. Sometimes the crossover inside the speaker can create a "short" or very low resistance, forcing the receiver into protect mode.

I ran into this with a Definitive speaker.
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by kkpro  /t/1521208/raising-volume-kills-the-receiver-possible-reason-s#post_24446047


Try hooking up the speakers on at a time and turning the volume up. Sometimes the crossover inside the speaker can create a "short" or very low resistance, forcing the receiver into protect mode.

I ran into this with a Definitive speaker.
Quote:
Originally Posted by whoaru99  /t/1521208/raising-volume-kills-the-receiver-possible-reason-s#post_24445716


Hard to say.


Could have been a fault within the receiver, or something with the connections, or one of the speakers.


Problem is, now that it's all disconnected, you may never know for sure. At this point I'd check the loop resistance of the speaker wires+speakers at the point of amplfier connection. 'Bout all you can do at this point.

Like I mentioned, I did check all wires and speakers and all seemed fine at the receiver end as long as resistance/short is in question. Resistance was around 8.5-9 ohms for all except the different one of the brand/model that is around 4.5-5 ohms. Obviously no short exists in the setting. What else can be tested?


Hooking up speakers one by one is out of question now because simply the receiver is already killed and no longer functional. I do have another receiver in hand but I don't really want to put it at stake. This is a costly test to do because each time I hit the soar spot, it kills the receiver once more. I hope someone with more experience would help me find the source of the problem.
 

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With your other AVR try connecting all but the CENTER speaker. That center speaker sounds to me to be the problem one. It may be below the 4 ohm rating. If the others work I would think that it is indeed the center speaker causing the problem. Do you have a friend with a different type of center speaker to try out? Also may want go over to the AVR after running without the center speaker to check if it is overheating. Touch the top to see if it is hot. As for being costly yes it is but really what are your other options. Of course the best thing to do would be to upgrade all of your speakers if possible. That could be costly depending on which speakers you decide to try.
 

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Quote:
Originally Posted by raminolta  /t/1521208/raising-volume-kills-the-receiver-possible-reason-s#post_24446768



Like I mentioned, I did check all wires and speakers and all seemed fine at the receiver end as long as resistance/short is in question. Resistance was around 8.5-9 ohms for all except the different one of the brand/model that is around 4.5-5 ohms. Obviously no short exists in the setting. What else can be tested?


Hooking up speakers one by one is out of question now because simply the receiver is already killed and no longer functional. I do have another receiver in hand but I don't really want to put it at stake. This is a costly test to do because each time I hit the soar spot, it kills the receiver once more. I hope someone with more experience would help me find the source of the problem.

Using a meter does not truly test the impedance. There is an ohm meter which sends a 1K test tone that measures the impedance. Also, as the different frequencies are applied to a speaker, it changes impedance. For example, some Def Techs may start out at 8 ohms but dip to as low as 2 ohms. But this is all a moot point because you want someone to tell you what the problem is and not help you to try to figure it out on your own.
 

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You probably need to talk to the repair facility and find out EXACTLY what they repaired in the unit... ie. common circuit, specific function circuit, output, input, etc. That will probably tell you more about where to look in your setup.
 

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Quote:
Originally Posted by raminolta  /t/1521208/raising-volume-kills-the-receiver-possible-reason-s#post_24445469


I noticed while all other speakers are 8 ohm, this one is a 4ohm speaker! Can this be the reason behind what has happened?

4ohm speaker requires twice the amperage to drive. Your 809 has a settings, from what I can find out, to tell the amp that it is connected to a 4ohm speaker so that an internal current limiter will be inserted to prevent the damage to amp. Since you didn't do such change from the looks of it, it is possible that the center channel amp got burnt out due to excessive current.
 

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Discussion Starter · #10 ·
I got the TR speakers off Ebay a few years back. Actually, as kkpro mentioned, I was measuring the speakers' resistance not their impedance. According to my measurement, the TR speakers were showing around 8ohms while the center channel was measuring around 3.5-4ohms. For an 8ohm impedance speaker, 8ohms resistance is actually higher than it should be. Normally a speaker with 8ohms impedance has a lower resistance measurement of around 6ohms. In other words, my TR speakers might have an impedance higher than 8ohms even though the specifications claim 8ohms and the center channel might be have an impedance of 6ohms!


So the culprit might actually be the TR speakers, not the center channel (which is of Polk Audio brand, btw). In one of the threads jim97219 linked here, they talk about TR speakers killing some amplifiers due to their odd impedance. I am still waiting to hear from the service center about the cause of damage.


In any case, it seems probably, the best solution (and the only solution that comes to my mind as of now) is changing all wiring and speakers before killing my receiver once again.


Thanks for all the responses. I got a set of JBL speakers that I am going to test soon.
 

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Discussion Starter · #11 ·
I got my Onkyo receiver back from the repair center. They told me a transistor needed to be replaced which was nicely covered under warranty. Moreover, when I asked why this happened, the technician said: "If you raise the volume on any receiver, at some point you may either kill your receiver or the speakers. It's not about this particular receiver". What do you think? Can this be true. Are other people really careful not to go above a limit on their receivers? I am really surprised. Receiver and amplifiers have been around for many decades and there is still no protection system implemented in them?! They are just use some replaceable fuses (like they do in electricity wiring, cars, etc.. I am puzzled.
 

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I had a Sony ES 5.1 reciever it was about 4 yrs old when it started to do that for a couple of days (turn it up and it would shut down ) ............just before it blew the fuses and outputs it wasn't a speaker problem either it just did it for some reason.
 

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In my case at least I was not turning it up extraordinarily loud only ~ 9:00 on dial when it started acting up . I have a dedicated 2.1 channel system with separates for critical music listening that is much better than my 5.1 system for music .

It was just the luck of the draw some AVR's break prematurely some don't . I'm not a fan of using 4 ohm speakers on an AVR though .
 
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