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Discussion Starter #1
I have an Onkyo HT-R340 which turns itself off on occasion if there is a loud sharp sound. This mainly happens with DVDs but also with the TV at times.

This is a recevier from a HTIB and has a passive sub-woofer. I disconnected the sub but it still occurs.

Any ideas what may be wrong with it? And if it may be an easy fix such as simply opening it up and giving the unit a good cleaning? Anything I should look for under the hood, such as browned out components?

This is a 2+ year old refurb model, that was only about $100, but I am curious about what may be causing that to happen. I don't mind cracking it open and messing with it. I have replaced it with a Denon AVR-591 and will put it on recroom duty if it works.

Any ideas are welcome. Thanks.
 

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Since it only happens during high volume passages it is likely a protection thing. Rather than blowing it is shutting down. Opening it up and cleaning it won't help. You can also check to make sure none of the speaker wires are touching and causing a short - triggering the protection mode shutdown. But if that was the case you would expect it be happening regardless of how loud things are getting.
 

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Yeah, make sure all your speaker wires are connected probably. You are using all the original speakers?
 

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Did it start happening very recently? Do you still have humid/hot weather in Ottawa? I have seen lots of electronic stuff over the years that packs it in or starts acting up whenever it gets very humid. Like the Dell PC I'm typing this on, cough... You'd think the A/C would cover it, but I can definitely correlate it with this type of weather. Maybe just opening the Onkyo case top would work, until the weather settles down (what I do for the Dell).

Besides the other stuff the guys said.
 

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Try eliminating what speaker is causing this protection to happen by removing them one at a time (from the amp). Once you have found the channel that this is happening on re-connect it with one of the other speakers to narrow down the problem to either the speaker or the amp. Amps that go into protection are like breakers in your electrical panel, the more often they trip the weaker/more sensitive they become.
 

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Discussion Starter #6
Thanks for the tips. I will follow up on these and see if it this is the problem. The speakers are from a Panasonic HTIB, and I got this receiver in order to get more HDMI and digital sound options.
 

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I have an Onkyo HT-R340
The speakers are from a Panasonic HTIB,
It's most likely a speaker impedance problem. I'm guessing the speaker impedance it too low for the amp and it's protection circuits are being triggered. You basically have two options. Either get speakers with higher impedance that are better matched to the receiver or run it at low volume to keep the overload circuits from triggering.
 

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Discussion Starter #8
It's most likely a speaker impedance problem. I'm guessing the speaker impedance it too low for the amp and it's protection circuits are being triggered. You basically have two options. Either get speakers with higher impedance that are better matched to the receiver or run it at low volume to keep the overload circuits from triggering.
I should have added in my post that when I bought the Onkyo, I checked the impedance specs between the speakers and the receiver to make sure it wasn't out of whack. Both HTIBs ran similar rated speakers. It has also been in use for about 2 years without a problem until now.
 

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From my experience I believe the Panasonic speakers are either 3 or 6 ohm, most amps now are being rated for 6 ohm rather than 8 ohm impedance, I am not sure why as almost all speaker manufactures are still producing speakers in 8 ohm. I am not sure about the impedance for the amp but since it is an older am I doubt it has been rated to 6 ohm. Like I said earlier go though the amp speaker by speaker to find out which channels it is protecting on(check all). Once you have found that out it will be easier to decipher what you need to replace.

I don't have any experience with Onkyo amps but I like Scarybob has noted there is probably an impedance problem and it has finally weakened the amp enough to put it into protection
 

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I am still pushing my "why NOW" hypothesis. :) Borderline stuff (load/impedance) does not like this weather. It is a rare Onkyo AVR that doesn't run rather hot even at regular times.

I would go so far as to say that "most" speakers sold for regular AVRs (not HTIB) in HT systems are 6 ohms these days. Typically they say "8 ohm compatible" or some such nonsense, which means 6 ohms.
 

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Discussion Starter #12
Mea Culpa, the rear surrounds were 4 ohm. The rest are 6. My better half is a bit hearing impaired and the volume tends to go up when she is watching TV or a movie on her own. Looks like when the volume went up, or spiked during a movie with some dynamic range that triggered the shut down. Interesting that it turns right back on.

As to the "why now" after 2 years, maybe degradation over time, or humidity. This wasn't a high end receiver to begin with. The manual says if the protection circuit has been triggered there is a reset function, but the description is if the recevier does not turn on at all. So that may not apply.

My new Denon is a much better receiver, but I have another set of small 6 ohm speakers that I will use in the interim.

I won't have a chance to play around with the receiver for a while, but when I get a chance I'll try variations of speakers with different ohm ratings and see if I can get it to be stable and bring the thread back.

Thanks.
 
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