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Receiver in Protected Mode - no sounce output

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I have a Sony receiver and once in a while it will go into a "protected" mode (the display says so) and I will lose all the sound while playing DVDs - especially Sci-Fi with a lot of sound effects.

I noticed it happens more frequently when I have the volume pumpped up and/or when the "base boost" and "equalizer" feature were turned on.

I fiddled with the equalizer adjustments and it did not help. It seems turning down the volume is the only way to reduce the sound been shut off. And I am talking about way low on the volume like 1-2 notch above the mute.

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What amplifier is it? As in the model number.

There are lots of reasons this can happen, too high a current, to high a voltage, To much heat, etc... But there are some known issues with certain amplifiers.

Let me know which yours is...


Thanks for the quick response. I had to go home to find out my Sony receiver model number before I can reply.

I have STR-DE835. Checked Sony's web site. It is no longer to be found. I bought it 3-4 years ago (=399 years in Receivers' world.)

As for adjustments, I reset it to manufacture settings several times and still had the same problem of getting into the "protected" mode and the receiver just cut off the sound and start flashing the display.

Hope you can help and give me some pointers.
Hi, I have spoken to a few people with similar problems with Sony Model receivers in the STR range of ones. Unfortunately, they all seem to agree that once the system starts doing that it is virtually a goner. You can bring it down to be serviced they stated, but they also said it would probably work out better in the long term to buy a new one. Two of them had similar problems, one had it with your model.

The main reason is most likely overheating at some point and this causes damage. The protection mode is built in to prevent damage, but unfortunately it still usually occurs.

Speak to your original dealer about advice and also speak to sony diretly. They have a customer service number on their main website.


How many watts do you have under the hood there, nsun38?
Bass will use all your power. Switch it off (or at least, flat) and an amplifier will stop gasping for breath. Make sure it is cooling well; no tight shelves with glass doors, all sealed up.
Your Sony's protection is designed to prevent amp damage, should the resistive-load on the amp (the load's impedence, ie. your speakers) fall below a certain point. A good amp is stable into a 4 ohm load; an (ahem) inexpensive design can start to sweat hard if the load falls to 6 ohms or even below 8 ohms!
Check your speaker wire carefully for any shorts, little stray strands or whatever. Turn the reciever dead flat. Check it out with a CD, maybe somthing acoustic.
If you are playing SciFi DVDs, you would be amazed by the wattage-requirement of the heavy bass - it rumbles, right?
See if you can weasle another pair of speakers somewhere, any ones, little ones or whatever, just to test. Your reciever might miraculously become powerful again, on a different pair. Just to diagnose, you know?
I suspect that, at a certain frequency or frequencies, your speakers are presenting a low impedence to the Sony amplifier. (Some amps have a switch at the speaker wire binding-posts, 4 ohm or 16 ohm. You should select 4 ohm.)
If you like these speakers, spend some money on at LEAST 14-gauge speaker wire, preferably 12 gauge if you have long runs; it will help this problem. Lotsa air through the Sony, and lay off the bass.
I'll tell you a funny story Bob Carver told me. He said a fellow came to him, said his amplifiers were wimpy, they had no guts. Said when he turned it up, his amp would trip-out, protection. He was pissed-off, thought he'd been cheated.
Carver labs checked his amp (it was fine) and disabled the protection circuit.
Guy came roaring back the next month, said his speakers were toasted. Said it set off smoke-detectors. Bob Carver himself came down to greet the man, and feared he would be angry. Instead, the fellow was smiling, happy as a clam. He stuck out him hand and said "Man, I just want to shake your hand. That amplifier ROCKS!!"
This message has been edited since its posting. Latest edit was made on 30 May 2004 @ 14:55

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I have a Sony SDR-DE845 and its doning the same thing. I move it to my my summer home in a new enclosure (although not encased). It have Bose cube speakers and bought new Bose rear speakers (wall mounted). No problem watching TV but when I watch DVDs lost all sound and went into protect mode. Spent $200 fixing and watched a DVD agand and same thing happened! No problem before while watching TV. Love Sony products but should I get another brand? Can't afford fixng this.
I had the exact problem about a year ago. The Sony rep stated that something was causing a short and the protection circuitry would kick in. I had to remove all the components and then wait a few hours, then plug in one component at a time to see if there was a lose speaker/component wire. As unexpectantly as it started, it went away. Haven't had a problem in over a year and I rock movies like Lord of the Rings. It started when I was running Star Wars Episode II. If the speaker's ohm rating is compatable with the receiver, then look for a speaker wire that is not securely seated or another lose wire. Also, make sure you have plenty of ventilation so the receiver is not over heating- no objects blocking air vents or located in heated areas. These things will make the receiver shutdown so that it doesn't sustain any damage. Good Luck.
This message has been edited since its posting. Latest edit was made on 02 Jun 2004 @ 18:39

Silent Assasin
It would be worth checking that you arent using Bi-Wireable speakers, and if you are, that you have removed the metal connection between the two sets of interconnects if you using Bi-wire (ie: 4 strands). Many people find that their amplifier gets screwed up because no one has explained what do with the connections on the bi-wireable speakers.

Hey guys,

Thanks for all the great input. I am trying out your suggestions and will keep you posted if I can resolve my problem.

Big Thanks!
I have had my receiver unplugged for a couple of days with no components connected. When I turn it on it still says Protector. Must have some permanent damage.
Or 1 little tiny stray speakerwire strand, barely visible, shorting out...? (Hopefully) or you're bunned.
Pull the reciever out and examine closely.
A repair tech would drive it into a 16ohm resistance, then 8ohm, then 4ohm. If it trips-out on the first (16ohm) loading, it is truly cooked. Perhaps it could be repaired for $50 bucks or whatever.
Good luck

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A quick update.

I re-strand the wire at the connection the point to the Sony receiver a few days back, tested these commercial movies that would lead my receiver into Protect mode before and have no problem at all!

T2 & T3
Speed 1
X-men 1 & 2
Matrix 1, 2 & 3
Moulin Rouge (Oh, Be nice. It's a great muscial.)

I also notice the dramatic improvement in sound quality from my Bose. Now the house shakes without going into protect mode when I pump up the volume or when the "sudden" sound effects occur from the Si-Fi.

Thanks to all of you.

I will keep you posted if the problem happened again.

you might want to try this simple step. It might be your solution too.
Thanks for the info, however I did chage my wires to the rear speakers before I used my repaired receiver and still had the same problem. Receiver is still in protect mode. Can't belive its a front speaker problem. I've bought a new Yamaha receiver. Any way to test the wires before reconnecting to avoid this problem with my new receiver?
nsun38, I can totally understand your movie test selections, up until Moulin Rouge... DUDE!!!!

Silent Assasin
Glad you figured it out.
95% of the time when this happens, it's caused by frayed wire(s) at the receiver end or at the speaker end. Anyone else having this problem, retwist your wires and re insert. Actually be better to use banana plugs on receiver end.
This will also happen when trying to drive 4 ohm speakers with a receiver meant to drive 8 ohms. Mostly happens when volume is turned up.
In case anyone has intermittent / unexplained symptoms, here's what happened to me earlier tonight.

My TA-VE215 (DTS AV reciever) went into PROTECT mode earlier tonight and wouldn't stay on, no matter what. Trouble was, I'd get sound for about 1 second (after the self-test/init), and then it would shut down. Thinking about it, I had noticed another glitch a while back, but cycling power fixed it that time, and I filed it under unimportant.

Well, it turns out that the fan wasn't spinning. By nudging the fan slightly I could make it spin, and this would make the unit stay up without any PROTECT message. On the other hand, if I manually breaked the fan to a stop, the unit would complain and shut itself down.

Wondering if perhaps the fan had died way back and slowly cooked my poor little transistors, I checked them all with multimeter. Nothing wrong there, so now it's off to Maplin to find a replacment fan (SUNON GM1204PKV3-A).

Another point to remember with any amp is basically look inside it and if its full of dust which is very common, that can also trigger the temperature sensitive cut out switch. So vacuum it out carefully and try again. Oh and another thing before i forget, if your speakers which you are using have been severely thrashed in the past, it is possible that the coils inside the woofers can overheat and cause either a slight short accross the coil or even a complete short. (This is caused by the coil slightly melting accross the windings). So that would be like shorting the speaker wires out directly. You might not neccessarily hear this either, it would also cause lots of strain on the power transistor in the amp.
hey everyone... Exact same problem here.. I have a STR-DE845 and the sony rep said that sense I was able to play cd's in my cd player ok that my receiver was perfectly ok.. it HAD to be either the link between the receiver and dvd player or the dvd player itself.. well after $40.00 for new cables and $130.00 for a new dvd player guess what ? SAME PROBLEM so $170.00 later and I am still with the same problem and now I have a choice of spending $130.00 to get this one fixed or bite it hard and buy a new one .. but you know.. I could have really used the $170.00 towards a new one
Lyndy that's just silly (no offense)
You could easily try the DVD player on another stereo using a variety of cables, to determine that it's just fine :-)
I could have really used the $170.00 towards a new one
Well you could have used the $130 - sounds like you have some dandy new cables, though...
If you follow all the advice in this thread, perhaps you can bring your Sony back from the dead, good luck!

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