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Marius

vertical lines on many XE computers

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Hi

 

Sorry for asking this, while I'm really sure this subject has been discussed several times. I really can't find any good information about it, so I started this new thread.

 

In my house I've stored about a zillion atari 8bit computers, and around 50% is an atari XE. A lot 65xe, 800xe and a bunch 130XE's.

 

They all have the GOOD GTIA chip (I alreay replaced the buggy one).

 

But I really "hate" those vertical lines I see on the screen.

 

When I turn on my 800XL and look at the blue screen it's all blue, and no lines are there. I love that, it is a nice and quiet blue screen.

 

When I compare that with the sharper view on XE, with those lines, I really prefer the XL screen.

 

And those lines do 'move' when there is RAMDISK and PBI acces too. So it is not only ugly, it is also annoying.

 

I hope there is an easy fix for this (like removing or exchanging a resistor or a capacitor). I know there are several video upgrades around, but I've done some of these and they did not fix the vertical-line issue.

And I'm not interested in an expensive solution with VBXE.

 

So please let me know, what else can be done.

Marius

 

p.s. I'm using PAL atari's, and only with SCART (video composite)

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Hi

 

Sorry for asking this, while I'm really sure this subject has been discussed several times. I really can't find any good information about it, so I started this new thread.

 

In my house I've stored about a zillion atari 8bit computers, and around 50% is an atari XE. A lot 65xe, 800xe and a bunch 130XE's.

 

They all have the GOOD GTIA chip (I alreay replaced the buggy one).

 

But I really "hate" those vertical lines I see on the screen.

 

When I turn on my 800XL and look at the blue screen it's all blue, and no lines are there. I love that, it is a nice and quiet blue screen.

 

When I compare that with the sharper view on XE, with those lines, I really prefer the XL screen.

 

And those lines do 'move' when there is RAMDISK and PBI acces too. So it is not only ugly, it is also annoying.

 

I hope there is an easy fix for this (like removing or exchanging a resistor or a capacitor). I know there are several video upgrades around, but I've done some of these and they did not fix the vertical-line issue.

And I'm not interested in an expensive solution with VBXE.

 

So please let me know, what else can be done.

Marius

 

p.s. I'm using PAL atari's, and only with SCART (video composite)

 

i have that same problem..

http://www.youtube.com/watch?v=pAbR6zO1wYk

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You know... that vertical line problem (more like a faint white column), happened with Commodore 8-bits as well. Original 64's were fine (just as the 400/800), but along came with the C64c and the 128 and that's when I started noticing the lines. Since the 80's, I just wrote it off as a cheaper/chinsey video output section as the machines were starting to be built elsewhere and with fewer parts. The lines usually go away as soon as a program starts - but yeah, it's annoying when you're expecting a pretty blue screen or whatever.

 

And no, it's not a simple matter of shielding either. I've tried everything in that regard to no avail :(

Edited by save2600
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This is a frustrating issue and quite different to the vertical zig-zag lines often seen on the XLs. There have been lengthy discussions here about the XE vertical banding quiet recently, but from what I recall the issue is caused by a voltage drop, and it's something all the XEs suffer from to some extent. However, the quality of the picture is also heavily dependent on the monitor you use. While my XEs have vertical banding, it's barely noticeable on my TFT.

 

I also found that the 130XE Supervideo mod made the problem dramatically worse. The video output on one of my 65XEs was absolutely appalling after I performed the mod, presumably because the stronger signal was making the voltage drop more pronounced.

 

That said, my stock XEs look pretty good through both my LG screens. I use an ebay s-video cable with diode in it, which is designed to lessen the vertical banding problem. They certainly show up both my XLs, which even after careful modification still have some way to go to match the clarity of the stock XEs.

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Sorry for asking this, while I'm really sure this subject has been discussed several times. I really can't find any good information about it, so I started this new thread.

 

But I really "hate" those vertical lines I see on the screen.

 

I hope there is an easy fix for this (like removing or exchanging a resistor or a capacitor). I know there are several video upgrades around, but I've done some of these and they did not fix the vertical-line issue.

And I'm not interested in an expensive solution with VBXE.

 

p.s. I'm using PAL atari's, and only with SCART (video composite)

Same here on one of my 800XL (so it is definitely not only an XE problem). My personal explanation is that these lines are the interference of the main clock frequency (\Phi2) with the color carrier, which runs at 5/4th of the main frequency. All PAL Ataris have two crystals, due to the way how the PAL encoding works, and the phase-locking between the two crystals is rather naive. If the crystals aren't exactly in-sync, you get a modulation on top of the color or luminance carrier that looks like this.

 

Anyhow, just my guess.

 

If you want to play with that, the phase-locking of the two crystals (Y1 the main crystal, Y2 the color carrier) happens around C59, C60, C61, C111 and L8 in the 800XL. I don't know where that is in the 130XE since I don't have its schematics.

 

So long,

Thomas

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The vertical lines appear on NTSC machines as well. I can't speak of 130XEs (because I never owned one) but they do appear on my 800, 600XL, and 800XL. For the 800 the lines are barely noticeable with one exception (described below). For the 800XL they weren't noticeable until I installed Super Video XL mod (2.0 only). For the 600XL, well with RF output only, the display is pretty bad. I tried Bryan's tip, removing an inductor and bringing +5V directly to the vacant spot. This greatly sharpened the image but also introduced the vertical lines. (I could live with the lines but the 600XL also has bad herringbone patterns and they move constantly. I don't suppose anyone has a solution for this).

 

During all of the '80s and '90s I mostly used my 800 with a B&W composite monitor using the luminance line only. Display was absolutely sharp including the perfectly straight, black vertical lines. Connected to a color TV (RF input only) the lines were not detectable.

 

I seem to remember hearing that the composite video bypass, discussed in the Super Video XL article, decreases the visibility of the lines. I will probably try to verify this now that the subject has come up again.

 

- Steve Sheppard

Edited by a8isa1

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Thank you all for the replies.

 

Unfortunately the answers are not resulting in a solution so far :s

 

My XEGS computers do have a perfect image too (no lines). Strange that some (most) of my XE computers do have the lines.

 

I had one 800XL which had the lines too, but only after I removed a resistor. When I put it back, the lines where gone too. Perhaps that might be a solution for other 800xl owners?

 

I keep using my XL computers, because of the better image, but since I have really a huge collection XE machines, I would like to use them too... but then without those lines.

 

I keep waiting for someone giving the solution :D

 

Thanks

Marius

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Haven't 2 "fixes" for this been discussed here before?

 

One was disabling the composite output as it supposedly interferes with colour/luma output.

 

The other related to a cable someone was trying to sell here - IIRC it used a small capacitor to low-pass filter the luma.

 

The cable sounds like one to try - doesn't involve any modification inside the machine.

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but You should LOVE banding - its part of Atari legacy ;)

who knows - maybe VBXE should emulate the banding :D

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I kinda notice this when I hook up with chroma/luma onto a s-video tv and remember seeing it on a commodore 1702 monitor. I always assumed that was normal and payed little attention it it since I only see it on a graphics 0 screen with a blue background. I could make it disappear alittle with adjusting the contrast/brightness.

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OK, I tested lifting one side of R56 (75ohm on 800XL). I left positioned so I could press on it to close the connection and release to open it.

 

With R56 disconnected the severity of the vertical lines is roughly one third of what it is when connected.

 

Please note that my 800XL is NTSC, has the Super Video XL 2.0, and uses Bryan's tip to remove inductor L5 to pull +5V directly to the lower point of the now absent L5.

 

You results may vary.

 

Hope this information helps.

 

- Steve Sheppard

 

p.s before lifting R56 I noticed that the vertical lines exist via RF, via Y-C, but not via composite video.

Edited by a8isa1

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After Building my S-Video Upgrade kits (version 1.0), I started tinkering with this issue. What I found is that the Culprit behind the lines showing up is the lack of full voltage to one of the transistors in the original Atari video circuit. With this in mind I built the S-Video Upgrade Version 2.0, Which actually has it's own transistor on board and bypasses the original Atari luma circuit altogether. because of this I had to require the version 2.0 board to be powered (so It gets +5 from a spot near the power switch inside the Atari). but, It Definitely solved the problem. =)

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I kinda notice this when I hook up with chroma/luma onto a s-video tv and remember seeing it on a commodore 1702 monitor. I always assumed that was normal and payed little attention it it since I only see it on a graphics 0 screen with a blue background. I could make it disappear alittle with adjusting the contrast/brightness.

 

I partly agree with you. Indeed: it is most visible on a screen with one color. (It can also be any other graphics screen ofcourse with solid color background)

 

But... It is also visible in certain games. I really like the game RIVER RESCUE ... well ... it is causing nausea on XE. You are really focussed on a screen moving from right to left. But the vertical lines on the screen are not moving. So sometimes my eyes focus on those lines, while the game is scrolling ofcourse... aaargh, that really makes me "sick" ...

 

So it is hard (for me) not paying attention to it.

 

But you are right: in most situations you won't notice them at all, and with adjusting the TV it can be fixed a bit indeed.

 

thanks

Marius

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After Building my S-Video Upgrade kits (version 1.0), I started tinkering with this issue. What I found is that the Culprit behind the lines showing up is the lack of full voltage to one of the transistors in the original Atari video circuit. With this in mind I built the S-Video Upgrade Version 2.0, Which actually has it's own transistor on board and bypasses the original Atari luma circuit altogether. because of this I had to require the version 2.0 board to be powered (so It gets +5 from a spot near the power switch inside the Atari). but, It Definitely solved the problem. =)

 

Are you saying that version 2 of your video upgrade fixes the vertical lines issue?

 

Or do I understand wrong?

 

Thanks

Marius

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Are you saying that version 2 of your video upgrade fixes the vertical lines issue?

 

Or do I understand wrong?

 

Thanks

Marius

 

It Has Fixed it on every unaltered system that I have installed it in.

 

 

So Far I have installed it in 9 different systems. 4 - 600XL's, 3 800XL's, and a 130xe. one of them (the 130xe) had a Ben Poehland upgrade in it and it still suffered from the lines a little bit. But My Personal 130xe, that was untouched, had no problem. The picture was beautiful.

Edited by kjmann

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Wow. This is an early Christmas present. I'd already done the Super Video 2.0 mod on one of my 800XLs, as well as running a 5v supply to the bottom of L5. The picture was slightly improved over stock but the vertical zig-zags were terrible. I'd forgotten how bad until I fired the computer up tonight while figuring out how to fit a RAM upgrade. So I went to check up on the SuperVideo 2.0 instructions here and realized I hadn't bothered with the compostite video switch. Well, since I have no intention of using compostite video in this lifetime, I desoldered R56 altogether and the result totally blew me away:

 

Before:

 

post-21964-126168458497_thumb.jpg

 

After:

 

post-21964-126168462963_thumb.jpg

 

Honestly it's hard to convery the difference in photos, even though there's a marked difference in the snaps. No more horribly distracting vertical zig-zag lines and intrusive artifacting all over the place. The output is nearly as clean as my stock XEs (both of which have a lovely picture). There's just a little more ghosting/shadowing around the letters on the screen which I'll try to fine-tune out with selective mods. But this really is night and day. I'd recommend anyone to disable the composite video output (on the XLs) after seeing this. It's made a machine which was just nice to look at standing in the corner a pleasure to use as well.

Edited by flashjazzcat
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Hello guys

 

I never liked the idea of putting a switch in there. There has to be a better way.

 

greetings

 

Mathy

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Before:

post-21964-126168458497_thumb.jpg

 

After:

post-21964-126168462963_thumb.jpg

That's awesome. I will try this on my 130XE. I did a super-vid mod to it a while back, but the output going to my scan doubler is rather noisy.

 

Stephen Anderson

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That's awesome. I will try this on my 130XE. I did a super-vid mod to it a while back, but the output going to my scan doubler is rather noisy.

The output should be amazing on the XE with that mod. I too have an XE with the super-video mod and the vertical lines were made worse afterwards.

 

My next question was going to be: how do you disconnect the composite video on a 130XE?

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Reading elsewhere, puppetmark said it's difficult to disconnect the composite on the XE without disconnecting the video modulator, which cuts out amps required for the signal. He suggested replacing L31 with an 84pf cap.

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Reading elsewhere, puppetmark said it's difficult to disconnect the composite on the XE without disconnecting the video modulator, which cuts out amps required for the signal. He suggested replacing L31 with an 84pf cap.

I got to chatting with a buddy last night so the 130 never made it down to the workbench. Thanks for the info. I know I don't have any caps that small. Maybe I'll try removing the modulator, I know I will never use it.

 

Stephen Anderson

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I got to chatting with a buddy last night so the 130 never made it down to the workbench. Thanks for the info. I know I don't have any caps that small. Maybe I'll try removing the modulator, I know I will never use it.

If you do these mods, can you jot down what you did? It would be appreciated: I might follow suit.

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WOW. I removed the RF modulator and the picture is now crystal clear! It's rather difficult to remove the modulator without damaging the board. You absolutely have to have a high wattage iron to remove the solder from the case lugs.

 

I desoldered the 5 pins from the RF modulator itself, not the 130XE PCB. When they were all free, I cut the pins between the modulator and 130XE mainboard. The reason I did this was to prevent any damage to 130XE mainboard. Now, the only thing holding the RF modulator in place is the 2 soldered lugs, one in front, one in back. I used a high wattage iron and large solder braid. With the RF modulator now out of the way, I removed the 5 pins from the 130XE mainboard one at a time.

 

The RF modulator is not damaged in the process, but I'm not sure what I will save it for.

 

Stephen Anderson

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WOW. I removed the RF modulator and the picture is now crystal clear! It's rather difficult to remove the modulator without damaging the board. You absolutely have to have a high wattage iron to remove the solder from the case lugs.

 

I desoldered the 5 pins from the RF modulator itself, not the 130XE PCB. When they were all free, I cut the pins between the modulator and 130XE mainboard. The reason I did this was to prevent any damage to 130XE mainboard. Now, the only thing holding the RF modulator in place is the 2 soldered lugs, one in front, one in back. I used a high wattage iron and large solder braid. With the RF modulator now out of the way, I removed the 5 pins from the 130XE mainboard one at a time.

 

The RF modulator is not damaged in the process, but I'm not sure what I will save it for.

Crikey! The picture on my XEs is good to start with so I'm not sure how to prepare myself for a drastic improvement! So that's basically it? If you can get it out in one piece without trashing the board, that's the mod done?

 

Some photos would be great!

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Well, I just did a similar mod and the picture is exactly the same as before! I didn't remove the RF unit completely (I don't have the desoldering tools at hand): I just removed the solder from the 5 pins on the Atari motherboard then snipped the pins off so they fell away harmlessly. No effect whatsoever. No matter, though, since the VBXE will be moving to this one soon. The real challenge will be sorting out the poor s-video output on the 65XE the VBXE is coming out of.

Edited by flashjazzcat

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