Ground Loop from Dish 622

[steve4810]

Ok, one other angle - your incoming cables from the dish are not properly grounded. Check and see if the line from the dish itself is connected to a ground block anywhere and the ground block is then connected to the house ground.

The Dish cables are the same they have always been and there never was hum before the 622. The only thing new besides the 622 is the 1000.2 but it is mounted on a plywood mount on a asphalt shingle roof, the same as the dp500 that it replaced. All the wiring is unchanged since day one 8 (I think) years ago. and through all those years and four prior receivers and three dishes there never was hum.

I know you guys are the pros but remember I didn't say anything about a ground loop. I just said I have hum. Ground loops cause hum but so do defective power supplies.

What about this, if it is the coax from the dish then the hum should disappear if I disconnect it. Wait and I'll try it....

No luck. Without a dish connected the hum is the same.

This does give me an idea though, I'll just disconnect everything connected to the back of the 622 one at a time and see if there is a path into the 622 that is carrying the hum (or is causing a ground loop)

Since this thread has run as long as it has and only two of us have hum on their 622s (and one is sure it's caused by a ground loop) then there is a one in a million chance I'm unlucky enough to have the one 622 with an internally caused hum.

 

[8bitbytes]

Well, certain parasitic infections from the tropics can make you think you hear a hum...

Keep digging, you are going to find it or send the 622 back fro a replacement soon!

 

[steve4810]

Well, certain parasitic infections from the tropics can make you think you hear a hum...

Sheesh! They told me there was very little chance of it returning.

 

[steve4810]

We have a winner!

Faulty 622 - 0
Ground loop - 1

I used a grounded extension cord and powered the 622 from another circuit and viola! no hum. Now I just have to find the... Ground Loop.

I'm thinking a disconnected ground wire or hot/common swap somewhere. But I'm damned if I know how that could be.

 

[highdefjeff]

This might help:

http://www.wowvision.tv/grounding.htm

 

[8bitbytes]

We have a winner!

Faulty 622 - 0
Ground loop - 1

I used a grounded extension cord and powered the 622 from another circuit and viola! no hum. Now I just have to find the... Ground Loop.

I'm thinking a disconnected ground wire or hot/common swap somewhere. But I'm damned if I know how that could be.

When I moved into my current home 8 years ago, I replaced every light switch and every outlet. They all had the wiring pushed into the holes on the back rather than the wire wrapped and screwed down to a side post. the wires can be pushed into the holes and still not make good contact. I had three outlets with that problem.

 

[steve4810]

When I moved into my current home 8 years ago, I replaced every light switch and every outlet. They all had the wiring pushed into the holes on the back rather than the wire wrapped and screwed down to a side post. the wires can be pushed into the holes and still not make good contact. I had three outlets with that problem.

I forgot I had a dining room light switch stop working a few years back and it was a push in wire that fell out.

Wow! I've got a huge job ahead. The only help will be that it is only on one of four 115V circuits with the problem.

 

[charlesrshell]

Hey steve4810, try one of them little testers that you plug in and test for correct lights to come on. They check the ground out too. I think that might find something wrong.

 

[steve4810]

Yeah, it seems like a good idea so I don't have tear open every outlet. Thing is I bought one years ago but I don't have clue as to where to start looking for it.

 

[charlesrshell]

Been there, done that. Get another one, they don't cost too much.

 

[mboron]

I had a ground loop problem in my three year old house that I could never find. It only became apparent after I got a plasma flat screen. In my case it was the video that was causing me headaches, the sound was fine. Anyways if all else fails, do a google search for "ground loop isolators" and pick one that seems to fit your problem. There are many different makes and models.

 

[steve4810]

There's more than one way to...
(I like cats so I won't finish that tired old gem)

On a whim I grabbed three to two pin plug adapter and let the 622 go ungrounded and the hum is 100% gone.

Now let's hear all the electric pros tell me how I'm gonna die when I touch the cold water faucet and turn on the 622 at the same time. And the dish pros that are gonna tell me lightning will burn down my house at any minute or blow the LNBs off the roof.

I DO NOT recommend anyone else doing this, but knowledge is power so I post in the spirit of informing all.

 

[charlesrshell]

Did you find your wall plug tester yet?

 

[steve4810]

Plug testers? Plug testers! We don't need no stinking plug testers!!

 

[charlesrshell]

So are you saying your 622 is the culprit??

 

[steve4810]

I guess I'm saying that when the 622 is plugged into the ground pin of the outlet in the den it hums but when it isn't plugged it into that particular ground pin there isn't any hum so I leave it ungrounded and I'm golden.

Could be that that particular plug has a ground problem. Could be that the 622 power supply is defective somehow.

I have to figure that the only reason it has a three prong plug to begin with is because it is connected to metal on the roof, or that there is so much gain that a grounded case reduces interference getting into the circuit.

The roof thing doesn't bother me and right at the moment there isn't any interference getting into the 622's circuits.

 

[charlesrshell]

I hope you find your tester and try that plug out too. Thanks for keeping us updated.

 

[highdefjeff]

Plug testers? Plug testers! We don't need no stinking plug testers!!

:haha:haha:clap

 

[klpye]

Directv Ground loop isolator

I have a hum that goes away when I disconnect my satellite cables to my Directv HD DVR. The DVR is connected to my complete 7 channel sound system which when not connected doesn't have a hum.

I've looked for Ground loop isolators and several reputable manufacturers have said that they don't work with HD satellite system. The Jensen Transformers Iso-max troubleshooting guide says DC power is required to the dish so I should use either use a gas discharge tube between the grounding block and the ground or to use a bi-directional coupler that works through glass.

Does anyone know where to get these/how to set up or a ground loop isolator for HD?

 

[charlesrshell]

I guess I'm saying that when the 622 is plugged into the ground pin of the outlet in the den it hums but when it isn't plugged it into that particular ground pin there isn't any hum so I leave it ungrounded and I'm golden.

Could be that that particular plug has a ground problem. Could be that the 622 power supply is defective somehow.

I have to figure that the only reason it has a three prong plug to begin with is because it is connected to metal on the roof, or that there is so much gain that a grounded case reduces interference getting into the circuit.

The roof thing doesn't bother me and right at the moment there isn't any interference getting into the 622's circuits.

steve4810, did you ever do more troubleshooting for your hum problem?