HELP with Denon AVR-788 Receiver

[leilaslass]

I bought a Denon AVR788 in April 08 and had professionals install it on a Sony flat screen with Polk speakers. Up until last week it has sounded fantastic. All of a sudden we keep getting this awful squeaking and ear-piercing loud static and then the sound cuts out or else it sounds as though the audio is underwater. At first I thought it was the cable but after several tries of turning the receiver off and on, only to have it work for a minute or two and return to the same behavior, I am thinking it is definitely the receiver. Anyone have a clue as to what might be going on? I don't know if I should have the people who installed it come out and investigate or if I should call Denon or Circuit City, or what to do. I did not buy any kind of protection plan so I'm on my own with this unless Denon steps up and helps. Since I didn't hook it up I am hesitant to start unhooking everything. I was curious whether anyone reading this might have had a similar problem. It has been a week now and the problem persists. Sometimes I can get the audio to work for maybe 10 minutes and then it's the same loud screeching and static again. I am clueless. Never had a home theater setup do this before. Denon was highly recommended but since it is less than a year old, I am hoping it is something they would repair or replace. Still, I'd be interested to see if anyone could post an easy fix on here. I doubt it since I can't make any clear sense out of the manual, but I figured it was worth a post if nothing else. Thanks.

 

[Adam]

Welcome to the forum!

I've never experienced that, but I wanted to mention that the Denon warranty on A/V receivers is two years. I don't know if Circuit City would take care of it for you, seeing as how you didn't buy their protection plan. However, Denon should certainly cover it - if it's the receiver that's doing it. Some other people here might have a better idea of what is going on with it.

Adam

 

[leilaslass]

Thanks Adam. It's so hard to know who to call and who to expect to fix the problem. It's even more frustrating to have a manual right in front of me that doesn't cover the problem I am experiencing. I did not know they had a 2 year warranty though. I appreciate your taking the time to respond.

 

[ParadigmDawg]

Would you be comfortable with unplugging everything and then just hooking up the main speakers and the DVD player? You could use a process of elimanation then and figure out what is going on.

 

[Adam]

Happy to help when I can. Sorry that it was only to give you info on the warranty and not a quicker solution (that might exist). If you click on the link that I provided, it has a section on how to obtain warranty service. Personally, I'd contact the place that you bought it (Circuit City, I'm guessing) and ask them first. They might take care of it or be able to tell you the closest place to call.


BTW, anyone else on here have any ideas on what might be causing this, or is taking it in for service the best route? Thanks.

EDIT: Just saw Greg's response. Excellent!

 

[Davemcc]

I would contact Denon directly on this issue.

 

[leilaslass]

Many Thanks

Thank you all. I think first I will try Circuit City since I contracted with them to have someone install it. I suppose it is possible because the Firedog people sent subcontractors out to install, they might actually send someone out to see what's going on before they have me unhooking things on my own. I was particularly interested to see if anyone reading this might have experienced the same issue or something similar. There are so many things hooked up on this new system it is difficult to tell who the culprit its. The picture on the screen is fabulous. If I put a DVD in the PlayStation, it looks great as well. My cable box is giving a good HD picture too. If I do a speaker check on the 5 speakers individually, they play their respective sounds. That's why I suspected the receiver. Just wanted to put my problem out there to get some feedback on what others might do, so I much appreciate the advice. If Circuit City can't or won't help, at least I will know contacting Denon is next. I think Greg asked if I was comfortable unhooking things and I did give it a fleeting thought, but have decided against it for now. If it was just a couple of wires, yes, but there is too much going on behind that receiver for me to start guessing. When I first had the whole system set up, I asked them to run eveything through the new receiver. It just seemed easier for general use and the installer said it was a good idea as well. Now I think that may have been a mistake because since that's the case, I can't even just listen through the TV speakers.

In any case, thanks again for responding. I have found that oftentimes on boards like these, I can find useful info by asking. When it gets resolved, if I have anything worthwhile to share for the fix, I will certainly post it on here.

Marlene

 

[Adam]

Now I think that may have been a mistake because since that's the case, I can't even just listen through the TV speakers.

They should be able to set it up so that you can listen through your TV. If not, we'd be happy to help. It almost surely would be a simple fix. I know that it can be intimidating looking at all of the wires back there, but it really isn't difficult to understand it once you learn about it. Just let us know if you want some help with that. We'd want to know the model number of your Sony TV, as well as that of cable box - just so that we could check what type of connection you have available.

When it gets resolved, if I have anything worthwhile to share for the fix, I will certainly post it on here.

Thanks! It's always great to find out how things go.

 

[bo14san]

I am having the same problem with the same receiver. Did anyone figure out the problem?? BTW, this site is awesome. Keep up the good work!!

 

[highfigh]

All of a sudden we keep getting this awful squeaking and ear-piercing loud static and then the sound cuts out or else it sounds as though the audio is underwater. At first I thought it was the cable but after several tries of turning the receiver off and on, only to have it work for a minute or two and return to the same behavior, I am thinking it is definitely the receiver.

Is this happening with all sources? If it's only on one source, it's there or the cabling. Turn the volume down- it the noise at the same level or did it decrease, too.

There's no reason to contact Denon unless the troubleshooting indicates that it is.

Again-

Which source(s) are being used when this happens?

Since it's only audio, unplugging the video cables won't be necessary and if the cables aren't labeled, do that for every one that you unplug, as well as making a list of where any cables are plugged into the receiver. That way, you can unplug all of them (there aren't that many and as long as you don't get into the "there's too many cables" mindset, it's not a big deal. Grab the list, grab a cable and plug it in where the list says it was.

If the receiver makes this sound with no sources plugged in, start looking at the speaker wires, at the receiver AND at the speakers. If too much insulation was removed and a strand from either the Positive or Negative is touching the other, it can activate the protection circuit or make it get flakey. If it worked for a while and you have a cat or dog, look at the speaker wires for evidence of chewing. If the speaker wires haven't been chewed on or you repair any damaged wire and it still makes the sound, call Circuit City and have it replaced.

 

[leilaslass]

Denon receiver problem

Well, when this happened, I called the Firedog folks who installed it and was advised to simply unhook the receiver and take it back to the store; tell them that the Firedog people told me to return it and ask for one to replace it. And it really was that simple, believe it or not! I did encounter some disbelief from the employee at the return counter, but when he got the manager and I showed my receipt and gave them the name of the person I spoke with from Firedog services, he did not give me a hard time. In fact, I could not believe how quickly they went and retrieved a replacement receiver for me. I had even forgotten to bring the remote to the original receiver with me and they were very good about letting me go home and get it. I returned it within 15 minutes. Once we got home, my husband hooked it all up again (he had literally put stickers where all the previous hookups were with labels) and it worked like a charm. Oddly enough, just this week we started hearing that same "static pop" again, so quite honestly, I have no idea if it's the receiver again or what the problem is. Maybe this particular Denon receiver just doesn't like my Sony tv or the Comcast HD box or the Polk speakers. I am clueless. Since they originally suggested that possibly the receiver was overheating, we constantly keep the door open to give it "extra" air but we really don't believe overheating was ever a problem. If you touch the receiver even now, after it has been on for hours, it is quite cool to the touch. And the cabinet we house it in was especially made for video/audio components just like this receiver and there is plenty of ventilation all around. The static popping sound only began again this week so we're just going to monitor the situation again. I can't say that Circuit City was anything but helpful though.

 

[Davemcc]

When does the popping occur, just randomly regardless of which source you're listening to?

 

[Highbar]

My first thought was that it was over heating and prematurely wearing down the components. How much space is around the receiver? My stand is specifically designed for AV gear and my receiver sits on an end table next to it because it's too tight of a fit. How long do you use it at a time? I'm looking for a new rack now that is open on the sides... only problem is pretty much nothing is designed for good old tube based TV's.

 

[highfigh]

I asked before and Davemcc asked again- is this with all sources or just one? If it's only when the TV is on, you may have a power/grounding issue. If you have cable TV and humming when that's on, unplug the cable feed to find out if it stops. If it does, you need an isolation adapter for the cable feed.

Two receivers won't usually have the same problem unless there's one cause. If you have equipment plugged in at more than location, you might be having issues with ground loops. If you see diagonal lines creeping up the screen, this is very likely.

 

[leilaslass]

More info

In my case, the noise only seems to happen when we are watching cable tv, at least for now. We haven't used the DVD player for quite some time though I watched a 2-hour movie this morning with no interference whatsoever. While watching TV last night, we experienced the static pop maybe 3 or 4 times.

Thanks for trying to help figure out the cause.

 

[highfigh]

In my case, the noise only seems to happen when we are watching cable tv, at least for now. We haven't used the DVD player for quite some time though I watched a 2-hour movie this morning with no interference whatsoever. While watching TV last night, we experienced the static pop maybe 3 or 4 times.

Thanks for trying to help figure out the cause.

OK, it sounds like the typical "Cable company installators didn't think it was necessary to follow the National Electrical Code, make sure there was no voltage on the shield and generally check for problems". If you have a spare coax cable that's long enough to replace the one that connects the cable feed to the cable box, cut the end off, strip the shield back and expose the center conductor. Replace the other one with this one by inserting the center wire into the receiver's input fitting without allowing the shield to touch the threaded part. You want only one conductor. If this fixes the problems, buy a voltage blocking connector.

Here's a link:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-192

Here's an isolating connector, but read the note for use with digital cable:
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=180-075&FTR=180-075&CFID=3023429&CFTOKEN=62282562

 

[mmarolia]

Same static issue on 788

I have had this same issue... Receiver worked fine for few months and then it randomly started developing static noise... if static increases too much, receiver shuts down sound... I have tried reconnecting all cables and resetting receiver etc...

statis is independent of source...

it does reduce with lowering volume...

and while static is there, I have tried to play around with all connections... and static disappears due to random action... eg. sometimes when I replug the HD cable from receiver... sometimes when I replug one of the speaker wires... sometimes when I change the source...

It was quite rare initially and frequency is increasing day by day... so its some internal component worn out I guess...