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Sr101

Help: Great picture... under White Static

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Hey guys! Just cleaned up an old 2600 Vader I got all boxed up for cheap!

 

Works well, with one exception. I'm using an RF to Coax connector straight into my TV(s, i tried it on both a flat and CRT) and I get some decent static.

 

Some games have a fair amount, some are a little crazy. Here's Donkey Kong and Yars Revenge for comparison and diagnosis.

 

http://imgur.com/a/c5tBe

 

Moving the RCA cable around DOES change the amount of static, and at one point I saw it completely gone!

 

Please tell me this isn't a board issue, if it's the RCA cable I should be able to replace that... I'm a young dude with little experience with soldering and that jazz.

 

Any ideas? Thanks in advance!

Edited by Sr101

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Hm, static usually isn't colored that way. It almost looks like the starfield effect in Cosmic Ark, which would mean the TIA chip in your console is broken.

 

But then, it goes away when you move the cable. So it must be static. Get a good, 75 Ohm, shielded(!) cable, best with ferrite bends. You do not have to pay for gold contacts or so. But the shielding is essential.

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Looks like the same problem that I had awhile back with a flea market find Vader I replaced the RF cable and problem solved.

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Okay, so I've got a cable, but the center "prong" seems to be quite a bit longer than the original Atari cable, and as such it's still producing static... Could I sand down the ends? I saw in a video with a similar issue that this could and should be done...?

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Just a hunch on my part, but I'd follow the videos advice. My cable fit ok, so I didn't need to do any modifications to the end.

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Looks a TON better. I made one HUGE stupid mistake though.

 

The cables casing, around the ends, it's too long. *slams head on desk*

 

That and, it seems that the connection gets better or worse the closer I get to the cable? Like too far and it gets bad, too close and it gets bad?

 

Anyway... will see if i can cut down the cables casing...

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Sounds like the shielding still isn't very good. Maybe the shielding of the cable has no good connection to ground.

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Looks a TON better. I made one HUGE stupid mistake though.

 

The cables casing, around the ends, it's too long. *slams head on desk*

 

That and, it seems that the connection gets better or worse the closer I get to the cable? Like too far and it gets bad, too close and it gets bad?

 

 

Sounds like the shielding still isn't very good. Maybe the shielding of the cable has no good connection to ground.

 

Thomas is right - that is exactly what's going on. The cable shielding isn't doing its job and the picture on the TV is reacting to the change in electric potential between you and the cable, and you're seeing the result in the RF signal. The shielding on the cable is not just supposed to keep the RF energy in, but also to prevent stray electromagnetic interference from outside the cable affecting the center conductor. Unless you have a proper crimper and know how to ensure the shield braid is making sufficient contact with the connector, it's probably better not to mess too much with the cable. You can safely cut the center conductor down a little bit if it's too long to allow the cable to seat properly.

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So just scraping it with sandpaper? I just got an elbow connector so that will likely let the cable fit :P

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without the elbow, the video looks great. Barely anything but a bit of a blurry picture, no biggie. But of course, the console won't close back up without the elbow connector, which makes it just as bad as before...

 

done for the night, any ideas would be welcome...

 

at this point I'm ready to buy another cable, anyone with a vader 4 switch have a specific cable they can recommend?

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If you are using the elbow connector, that is the problem, because normal Vader units do not have this, the RF goes straight into the jack on the board, then you maneuver the cable until the unit closes, it WILL close but to do it you connect the cable direct to the board, then put the motherboard into the TOP half of the shell first, do not lay the motherboard in the bottom half and then try to put the top half on. This is not how it's done

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I was considering trying the filter, sounds like a plan! However... getting the cable to fit... it sticks straight up for more than in inch, and i'm afraid the angle that the board fits into the top piece just wont allow it to fit... I'll try again though!

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Those ferrite beads sure help. But the shielding of the cable still should be grounded.

 

So a well fitting cable is first priority. If that does not work, you can still experiment with additional shielding like ferrite beads.

Edited by Thomas Jentzsch

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Cable can fit, after some tight closing, but it looks AWFUL closed, likely due to the force on the port.

 

Beads do nothing...

 

When I touch the grey box next to the port it sometimes makes the picture better... this has gotta be the cause.

 

so... what do I do? can anyone recommend a cable that will fit and not have this interference?

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With the "grey box", do you mean the shielding of the video section at the right. Or the bigger box in the center?

 

The former needs good grounding too. I am not sure how connection to ground is established, most likely by touching some traces on the board which are grounded. Maybe you can may the shielding box fit better. I think it is attached at the back.

 

The latter contains the chips. Maybe one chips or some parts inside this box became loose? You should have a look inside.

 

BTW: The static still looks odd to me. But that could be due the video processor of the TV.

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It's the rightmost side, and after touching it while playing several times, I can confirm that is helping a TON.

 

I'll have to look into getting under that safely, and update with pics.

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I have a feeling it's a grounding issue- when the controller is plugged in, it seems to look better. When I touch it, it seems to look better...

 

Very confusing stuff... any ideas?

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You probably do not have to open it, just make sure the casing touches ground somewhere. I am not an expert here, but maybe the soldering you mention is meant for that. And maybe it is broken somehow?

Or do you mean the foil tape as shown here (do NOT cut it)?DSCN3922.jpg

 

Try tightening the little tabs that run round the case as shown here:

DSCN3923.jpg

Edited by Thomas Jentzsch

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I apologize a ton for all these spammy(?) posts, but another huge breakthrough on this end. I seemed to have just confirmed there's a grounding issue!

 

https://www.youtube.com/watch?v=u2JWJa2oJYI

 

Now... while I have already asked a ton of random questions... how could I fix this? Thanks so much so far guys!

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