# Grounding the 722?



## RasputinAXP (Jan 23, 2008)

So I have the component output of my 722 running to the TV in the living room over cat5 . Pretty happy with it, but there's a noticeable buzz in the audio and horizontal lines rolling up the screen. It was worse before (I had run the Cat5 too close to AC) and now it's watchable if there's background music or noise but silent stuff? The buzz is overpowering.

A friend suggested that I may have to ground the 722. It's currently plugged directly into the wall, but does this mean there's something wrong with the actual grounding prong? Should I just plug it into the UPS I have on the rest of my equipment? Is there some sort of grounding screw that I can use on the 722? I know, I'm full of questions. What can I say, I'd like to have NO buzz 

Thanks.


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## TulsaOK (Feb 24, 2004)

RasputinAXP said:


> So I have the component output of my 722 running to the TV in the living room over cat5 . Pretty happy with it, but there's a noticeable buzz in the audio and horizontal lines rolling up the screen. It was worse before (I had run the Cat5 too close to AC) and now it's watchable if there's background music or noise but silent stuff? The buzz is overpowering.
> 
> A friend suggested that I may have to ground the 722. It's currently plugged directly into the wall, but does this mean there's something wrong with the actual grounding prong? Should I just plug it into the UPS I have on the rest of my equipment? Is there some sort of grounding screw that I can use on the 722? I know, I'm full of questions. What can I say, I'd like to have NO buzz
> 
> Thanks.


Did you try plugging it into your UPS?


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## RasputinAXP (Jan 23, 2008)

Just did. It's less obvious than it was but it's still there. Closer to a hum than a buzz.


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## Miner (Oct 29, 2004)

Sounds like a ground loop. Radio Shack sells ground loop isolator for audio you might try. I used to have a hum between my computer audio out and stereo and the isolator did the trick.

Are you using just plain Cat 5 for the transport, or a custom made system? If just Cat 5 it could be a bit of impedance mismatch combined with just general electrical noise. 

I hope you get it solved.

Miner


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## RasputinAXP (Jan 23, 2008)

Miner said:


> Sounds like a ground loop. Radio Shack sells ground loop isolator for audio you might try. I used to have a hum between my computer audio out and stereo and the isolator did the trick.
> 
> Are you using just plain Cat 5 for the transport, or a custom made system? If just Cat 5 it could be a bit of impedance mismatch combined with just general electrical noise.
> 
> ...


Passive baluns with Cat5e between them. The video's nearly perfect, it's just getting that hum out that would do the trick. I'll see about grabbing a ground loop isolator from the local Ripoff Shack.


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## Henry (Nov 15, 2007)

An inexpensive outlet tester will tell you if your outlet is wire correctly, if the hot and neutral are reversed or if you have a floating (unconnected) green wire safety ground. My guess is the latter.


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## RasputinAXP (Jan 23, 2008)

Yeah the ground loop isolator did nothing for me. I've found floating grounds in my house before, it wouldn't surprise me a bit. It would also explain a few surge/sag related problems I've had down there.


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## Henry (Nov 15, 2007)

RasputinAXP said:


> Yeah the ground loop isolator did nothing for me. I've found floating grounds in my house before, it wouldn't surprise me a bit. It would also explain a few surge/sag related problems I've had down there.


RadioShack or Wal*Mart should have the LED circuit testers if your supermarket doesn't carry one. Shouldn't cost more than $2/$3, if that much.


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## RasputinAXP (Jan 23, 2008)

Update time.

I plugged the Xbox 360 component cables into it, and it's flawless.

Now what? It doesn't flake out when it's connected to my TV locally. Do I need to amplify the signal with an active balun?


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## Henry (Nov 15, 2007)

Grounding issues can and will give erratic results. You should first establish whether you have a good ground before you perform any other tests. After that, you can search for shielding or amplitude or length-related issues.


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## RasputinAXP (Jan 23, 2008)

OK thread necromancy begin:

I checked the grounding in the box and it's good, so it's not coming from the wall or the UPS.

Interestingly, if I use a component video multiswitch and plug the 722 AND the 360 into the box the 360 inherits the audio hum as well, but without it's fine.


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## RasputinAXP (Jan 23, 2008)

UPDATE TIME!

Dish is sending a new 722 out for $15 shipping.


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## BattleZone (Nov 13, 2007)

Ground loops happen when you have circuits that don't have the same ground source. All grounds in the house should be connected to the main house ground, which should be connected to a ground rod that's installed below your power meter. In newer houses, this ground rod may be a piece of rebar that's set into the foundation, so it may be inside a wall. In older houses, you can usually see the ground rod on the outside a few inches from the foundation.

A common source of this problem is people trying to use cold water pipes (or even worse, gas lines!) as a ground source. Too often, these aren't back-bonded to the house ground, and even if they are, can still provide a secondary path to ground and cause a loop.

These types of issues are rarely solved by replacing equipment, and they're rarely easy to track down; you may literally need to open up every outlet and verify where the grounds are going. A plug-in tester is a good start and may greatly speed up the process if it helps you find an outlet or two with an improper ground or other problem.


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## SaltiDawg (Aug 30, 2004)

BattleZone said:


> ... All grounds in the house should be connected to the main house ground, which should be connected to a ground rod that's installed below your power meter. In newer houses, this ground rod may be a piece of rebar that's set into the foundation, so it may be inside a wall. In older houses, you can usually see the ground rod on the outside a few inches from the foundation.
> 
> A common source of this problem is people trying to use cold water pipes (or even worse, gas lines!) as a ground source. Too often, these aren't back-bonded to the house ground, and even if they are, can still provide a secondary path to ground and cause a loop. ...


Depending on the vintage and location of the home, indeed the water main (pipe) may be the ground for the electric service - it is in my 1973 vintage home in the MD suburbs of DC.


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## RasputinAXP (Jan 23, 2008)

OK, so the 722's been replaced and the buzz is still there.

I checked all of the sockets, upstairs and down and there's no problem with the electric. The tester comes back clean on everything.

I've replaced all of the cables between the 722 and the run, and the other end of the run and the television and it's still there.

The buzz is nowhere to be found when I plug the Xbox 360 into the exact same run. 

So far, I can't tell that this is a grounding issue, as it's only happening with the 722, and it's not remedied at all by using a ground loop isolator.

I'm completely at the end of my rope, here. I swear I just want to find some other way of doing this. The wife's ready to kill me. It's been a 2 month saga.


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## RasputinAXP (Jan 23, 2008)

P Smith said:


> I would try run temporary just long (100 ft ?) component/audio cable from 722 to that TV, it could help to separate source of the hum; your Cat5 cable could running close in parallel to electrical wires


(I couldn't PM you about this, either; told me I wasn't allowed!)

Relocated the run already; it didn't make the hum any better. Also, the same run with the same baluns using the Xbox 360 as the source has NO hum in the audio.


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## kevin d (Sep 21, 2005)

A couple of things to check.

1) The 622/722 has an issue with voltage on the component video outputs. Audio authority makes a devices to fix this:

http://www.audioauthority.com/techdocs/focus_1182_83_84print.pdf

You might also check to see if the 1184 has the same fixes for the component video as the 1183. Might fix the audio if it's not caused by the voltage on the component video.

2) Unplug the sat feed cable and see if the hum goes away. The dish ground (if there is one) or any other receiver's ground connected to the same dish might be causing the issue. You may need a ground isolator on the incoming signal line instead of the outputs.

Kevin D.


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## RasputinAXP (Jan 23, 2008)

Kevin, you may just be a lifesaver. I'll check out where I can get my hands on an 1183 or 84 and see what that does for me. Thanks a million!

ETA: Also, I know the dish is grounded to my cold water line in the basement. Is that sufficient?


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## RasputinAXP (Jan 23, 2008)

05/04/2009 7:05 A.M. OUT FOR DELIVERY 

Only a few hours to go...


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## RasputinAXP (Jan 23, 2008)

The answer is that the 1183 didn't fix the problem very much. It's still very audible. I'm going to see if I can return it for an 1184.


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## RasputinAXP (Jan 23, 2008)

The 1184 got here and it's still horrible. Going to play around with it for a bit, but now I'm really at the end of my rope.

I mean jeez, how much money do I have to throw at a problem?


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## RasputinAXP (Jan 23, 2008)

Swapping things around, I moved the 1184 upstairs and put it between the output on the wall and the input to the TV.

IT WORKS!!! NO HUM!!! NO MORE LINES IN THE SCREEN!!! F L A W L E S S!!!

Thanks Kevin!!


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## kevin d (Sep 21, 2005)

No problem, glad it worked out! Working with 2-3 racks full of equipment, running every TV in a house, all on different circuits introduces you to a lot of interesting problems. 

I can't remember how detailed the instructions are, but they should have said to put it on the receiving end. If you power it from the same ground/common as the source device, it probably will never work. 

Kevin D.


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