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Discussion Starter · #1 ·
I am having a strange problem and I am hoping someone can help me to understand it.


This is my setup.:


Dish: KTI 18x24 elliptical dish with integrated 4x4 switch. Not Sat C kit.

Receivers: Toshiba DST-3000 and Sony SAT-A4 in another room.

Display: LT150 project --> DST-3000's component out. Toshiba 35" direct view TV--> DST-3000's S-video out.


Problem:

All signals from even number transponders (e.g. 2, 4, ... 32) display a faint yellowish rolling bar on the 35" TV. The signals from odd number transponders look normal. This is true for both Sat A and B. As the result, some of the channels (including HDnet) while viewing on the direct view TV has this rolling bar which can becomes quite annoying after I am getting used to the stunning pictures coming from LT-150.


Now the strange part, when I view it on the LT-150 project which is connected to the DST-3000's component output, the bar is simply gone, for all the channels, even or odd transponers.


Since I only watch DVD and HDTV on LT-150 and I'd like to watch News and other programmings on the 35" TV. Can anyone help me to understand which component produces the rolling bar and how to get rid of it?


Thanks in advance!!!


AW
 

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I have the Toshiba DST-3000 and have noticed a different variation of the described problem. In my case, I see moving horizontal bars which appear greenish on flesh tones on odd transponders when I use the S-video output. This is very noticeable on foreheads during closeups of faces. This problem does not appear on even transponders or on the component output. This problem does not appear with my old RCA stb which only has S-video outputs.
 

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I have none of these problems. Winegard Oval dish w/integrated 4x4 arm. DST-3000 to a Tosh 50HX81. HD viewing via component, regular viewing via s-video.
 

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I've been through 5 DST-3000s to get 2 that work but I've never seen this problem. It sounds like a ground loop though. Do you have a cable TV input going to the DST-3000? If so, try disconnecting it when the TV is displaying the problem. Run all cabling entering the house through ground blocks. Get a plug in outlet tester to make sure your electrical outlets are properly polarized and grounded. Search the web for "ground loop" for lots of other ideas.
 

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Discussion Starter · #6 ·
Quote:
Originally posted by greywolf
I've been through 5 DST-3000s to get 2 that work but I've never seen this problem. It sounds like a ground loop though. Do you have a cable TV input going to the DST-3000? If so, try disconnecting it when the TV is displaying the problem. Run all cabling entering the house through ground blocks. Get a plug in outlet tester to make sure your electrical outlets are properly polarized and grounded. Search the web for "ground loop" for lots of other ideas.
Yes. I kind of suspect the same thing at first. I don't have Cable TV. I confirmed the rolling bar is from Sat Signal, as when I unplugged the Sat input and only left OTA input, the bar was gone.


BTW, the dish, and the four co-ax cables from 4x4 are grounded to the same 6 gauge gound wire, which is then connected a 8-foot ground rod I buried under the deck. The disk is mounted on the deck.


The part I don't understand is, if it is the ground loop, why would the bar only shows up on even number transponder signals. Also, why would it only display on S-video and composite outputs, but not component output?


Thanks.


AW
 

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Discussion Starter · #7 ·
Quote:
Originally posted by greywolf
I've been through 5 DST-3000s to get 2 that work but I've never seen this problem. It sounds like a ground loop though. Do you have a cable TV input going to the DST-3000? If so, try disconnecting it when the TV is displaying the problem. Run all cabling entering the house through ground blocks. Get a plug in outlet tester to make sure your electrical outlets are properly polarized and grounded. Search the web for "ground loop" for lots of other ideas.
Yes. I kind of suspect the same thing at first. I don't have Cable TV. I confirmed the rolling bar is from Sat Signal, as when I unplugged the Sat input and only left OTA input, the bar was gone.


BTW, the dish, and the four co-ax cables from 4x4 are grounded to the same 6 gauge gound wire, which is then connected a 8-foot ground rod I buried under the deck. The disk is mounted on the deck.


The part I don't understand is, if it is the ground loop, why would the bar only shows up on even number transponder signals. Also, why would it only display on S-video and composite outputs, but not component output?


Thanks.


AW
 

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Part of the problem could be that ground rod. Your equipment is running two grounds, the rod and the main house ground. The separate ground rod is usually a bad idea because of potential difference between the two. Internal wiring of the receiver could explain the component/S-Video difference. The odd/even thing is a bigger mystery. Is the multiswitch grounded? I forget whether or not it is electrically joined to the mast.
 

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Just got another idea. Since only the even number transponders on the 101 bird seem to be affected, there may be some corrosion or poor contact on the coax connection between the LNB and , IIRC, the 18V input on the right side of the multiswitch. Of course the switch itself may have a problem.
 

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Discussion Starter · #10 ·
Well, I hate to be the spoiled one. But the bar is seen on even transponders from both A and B birds. But I will double check the connection to the 4x4 when I go home today.


I agree second ground rod is a bad idea. The orientation of my house doesn't really leave me much of choices. The place I can install my dish is too far from the main ground rod. Luckily, the DST-3000 uses only a 2-prong power connector. So, if the co-ax shield is wired to the chassis, then the whole unit should be grounded to the new rod. I think....


Thanks.


AW
 

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Heck! You posted the A and B sat problem and I totally missed it. Instead I inferred the A bird from the transponder numbers. I've gotta think it's the switch or the switch's grounding.


You're welcome although at this point I feel the only help I've provided is as a sounding board.
 

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I've gotta quit shooting from the hip with these guesses. If the switch was going it would show up on the projector too. If any machine with a grounded plug is connected by an A/V cable to the receiver, the receiver is connected to 2 grounds. The cheapest quickest thing to try first is to replace the S-Video cable. I'd also temporarily run a wire outside between the 2 grounds to see if anything changes. That's it. I'm out of ammo. When you solve the problem, please post the solution.
 
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