We installed a simple system about a year ago that consisted of a Denon AVR-689 - Cox STB - Sony DVD - Samsung LCD. The equipment was on the opposite side of the room , so we ran a 50' HDMI cable to the display ( same cable we use all of the time). Everything was fine until last we the customer called and was having video issues and had called the cable company. The cable guy came over and bypassed the Denon and connected straight to the STB and it worked fine.

We went by and did some troubleshooting and concluded that the HDMI on the Denon was not working so we ordered an AVR-791.Today we delivered and installed the new AVR and everything seemed to be working fine except when you change inputs you would see some white pixelation on screen and then it would disappear within a few seconds. After about 15-20 minutes we lost signal and not it seems that the new AVR is doing exactly the same as the old one.We bypassed it and the 50" HDMI straight to the tv works fine with cable and dvd. We also tested a new HDMI across the floor with no luck. It seems as if something is taking out the HDMI protion of the AVR's. All devices ( including the tv) were power cycled several times and we are using the same manufacturers 3' HDMI as interconnects. Any ideas or has anyone experienced similar issues?

Wow! Low end Denon + Cox STB + 1 year old Sony + Samsung = Disaster!

Do yourself a favor and take Jeff Boccaccios class. That white pixelation you were talking about means something. You were lucky enough to be handed a tell tale sign of the problem and overlooked the obvious.

Brent, this guy needs a sales call!

I am certain that I have installed close to the same system any times. 95% of my jobs involve a low end Denon and a Cox STB. Most of them have a 12' HDMI but I have plenty of them with 30' -50' and have even used some 75' cables after days of troubleshooting HDMI baluns. Ethereal - Knoll - generic with no luck. I have run around buying leviton brand rj-45 ends , pulling out cat5 replacing it with cat6 on at least 2 memorable occasions. I very seldom have the pleasure of selling all of my preferred equipment and placing it in my preferred locations , and I hate to turn the jobs away . Heck I have to eat and these days it almost seems like a luxury at times. I have not been to any of this guys trainings but I have talked with Brent in the past and man that guy has some major HDMI knowledge. I do countless hours of reading and research online but I think my issue may have something to do with faulty component in the mix. I have heard of pixelation issue being the HDMI being at it limit without complete fail . and this is probably one of those cheap cables that is not tested individually for HDMI compliance but I have used many of them in the past and never have seen a bad one. Plus I used another cable across the floor for test purposes. I may have two problems here or maybe the inferior HDMI cable has caused something else to fail . I have never heard of this and do not even know if it is possible.

There is a whole lot more to HDMI than just the cable itself. When you run the cable direct you are cutting down the amount of information that travels through that cable and the amount of voltage drop seen between the devices. Is there a way you can run 2 shorter cables with a restorer in the middle?

Give us some of the troubleshooting steps you used other than direct connect.

Little background on signal loss.

Each meter of cable (Based on a high quality HDMI cable)
= 1 dB of signal loss
Each HDMI terminal (assuming proper circuit board design)
= 1 dB of signal loss (+/-)

So in planning a system with source, AVR and 15 meter cable (+/-) there is 19 dB (+/-) of signal loss out of the gate.

Now lets talk about the sparkle's.
These indicate that the High Speed Data (Video/Audio) has started to collapse, while the AVR is not the culprit it does add to the loss.
We have found in testing that there is a wide variance in the HDMI output signal level with cable STB's (Motorolla is the worst).
The solution is a signal restorer (ours is the SR-1) this will return the signal level to what the source "should" be outputting.

Brent, I have asked this question several times in these forums but am not sure i ever really got a cogent answer. The idea that there would be signal loss when the hdmi stream passes through the avr would make sense if the avr were merely repeating the signal it received upstream from the source.

However, we know that is not the case, as the avr needs to decrypt the stream and then encrypt it with a different key. Since the avr is therefore sending what is essentially an entirely new stream of data, how is it that the signal would not leave the avr with the strength of a new signal (ie without any loss?)

"Give us some of the troubleshooting steps you used other than direct connect."

-Exchanged the AVR with a new one , and it worked fine for a relatively short time.
-Used a new HDMI cable across the floor
-I know the Cox boxes are finicky but the AVR will not show the OSD over the cable

Thanks for the input Brent but this lady will blow a gasket if I tell her she needs to buy a $300 part to make this work correctly after it has been working flawlessly for almost a year and I sure do not see myself eating it at this point.If I can not find a solution then I see myself putting the old AVR back in and running component video to the tv. Sweat equity is a lot easier to spend these days than real money. If the issue would have shown itself from day 1 or even the first week it would be a lot easier fro me to justify it to her.

Entry level products (AVR's under $1000. +/-) do not rebuild signal level.
They can and do de-serialize the audio portion and overlay OSD but this does not mean that they improve signal level (it is all about cost).
Our restorer cost (retail) about the same as an entry level AVR (and we are not making a killing).
As you increase the retail price of an AVR you will (or should) get better video processing (mostly analog to digital) and better signal path design/build (which will reduce loss).
Proper HDMI board design/build is the single most expensive cost item in the build of an AVR, that being the case mfgr's do as little as possible to meet market/price requirements.

I received a video today taken by a dealer where he pulled the case off of an AVR and found that that HDMI portion of the AVR (in the top right front)was connected to the rear panel jack by an actual HDMI cable w/ right angle adapters (which can add to the loss) instead of a proper trace eq'd & balanced signal path (I will only say that it was NOT a Denon product).
This in my opinion is a cheap/shoddy way to do this.

Have you tried another source?

I a call with the same issue today, STB would not work through the AVR / balun setup but the Blu-Ray (1080P) worked just fine.
Since the Blu-Ray requires a lot more bandwidth at 1080P than the CATV STB at 1080i we can know that the AVR / Balun was correct.
What is left?
The cable box.

Take another source to the job and check the system.
BTW:
Is the STB on top of the AVR?
Is the STB on a poorly vented shelf?
Is the AVR on a poorly vented shelf?
Is the equipment in a poorly vented cabinet?
Any of the above will cause your issue. as the HDMI boards heat up the capacitance increases which will lower possible rez output (there are also impedance issues caused by heat).

Your customer will add her blown gasket to the thousands that have blown over HDMI.

Being sarcastic, your problem was that after you installed that cable, you did not freeze time.

The HDMI crowd should have told us the truth, told us that last year's cable won't work with this year's signal, told us never to make a permanent installation of any long HDMI cable. At least Brent's got a product that can cure the problem. I hope it can cure it every time!

Brent sells time freezers?? :)

Does the avr's own on screen display show up ok?

You are making it sound as though the video signal just passes through with only the audio and OSD being processed. However, the TMDS channels have all of this data (i.e. audio, original video, OSD, etc.) mixed together in a brand new stream that is re-encrypted with a new key, right? So, there is no actual bits in the original signal that just pass through the AVR, right? What goes downstream from the AVR is an entirely new bitstream - it has to be, since it is encrypted with a new key. What am I missing, here?

There is no new key.
The key is from the source.
AVR's are not considered a sink (they can only extract audio not video) or a true source, analog up converted data is just another input to the HDMI switch (and yes I know that basic EDID is added by the I/P digital converter) .
The OSD is a non-secured (by DCP) overlay.
With an AVR it is garbage in, garbage out.
Also note that signal loss (by connector count and wire distance) is not the only issue here.
Circuit board design (and build quality) are very critical to minimizing loss (or adding to it).
AVR's tend to catch the most blame when things don't work, what you should be looking at is the source.
The source sets the signal level standard for the system, more is ALWAYS better (at least in reference to this, it is possible to overdrive HDMI).

What he said!
I never bet on a cable longer than 6 meters, you will get burnt (someday).
Right now 6 meters is the safe(ish) limit to 3D, we will be able to go will beyond that come CEDIA (and help current longer cables work with 3D, 1.4A needs).

But still "I never bet on a cable longer than 6 meters".