Quick & Easy Video Upgrade for 800XL

[+bob1200xl]

OK - my two cents...

 

You need to improve the bandwidth of the video in order to draw nice, fat vertical lines. But, the faster you drive the signal, the more noise and corruption that leaks in. That's why some monitors look really good and some don't. It all depends on their bandwidth verses what your computer is sending out. Sometimes, the limited bandwidth of a cheap monitor filters out a lot of nasties, where a good monitor will display them correctly. (and ugly)

 

The other issue is the circuit board itself. The harder you drive the video, the more current you draw from the Printed Circuit Board wiring. A really well designed board will be able to supply that instantaneous current without introducing noise. A poorly designed board will not. Noise is actually generated on the power lines themselves, which spreads it all over the system.

 

Have you noticed noise on the left side of a GR.0 screen that looks like 9 vertical bars? That is noise from the refresh cycles in memory.

 

The 130XE (and, I assume, the 65XE) are designed with high current, high speed video and they work pretty well. You would think that just duplicating the XE circuits in a 1200XL, for example, would give you the same, nice video. Try it - it won't. The board itself can't supply the necessary current.

 

I use a Teknika MJ-22 monitor on my main (modified) 1200XL and it looks good, but the same system on one of my LCDs may or may not.

 

I don't think that there is one, single solution for this problem. Maybe a digital HDMI interface...

 

 

Bob

 

 

 

 

Having done this upgrade on a second 800XL, I really like a crack at getting rid of those vertical jaggies. Clearly they're part of the luma signal. Any techies had any thoughts on this, or better yet, successes?

[flashjazzcat]

Thanks for the explanation. For someone like me who doesn't yet understand much about electrical theory, it's important realize why the circuit can't just be modified so that it's the same as that in the XE.

[+Larry]

Yes, Bob, thanks for the explanation. I noted the same about the "cheap versus good monitor" results quite some time ago, but of course, never really understood why. It still amazes me that when the 1200XL came out, reviewers raved about the beautiful, "improved" video. I think they must have reviewed prototypes or "tricked-up" models.

 

This is a really good thread and one that people can come back to again and again, since most XL's suffer. It really should be "pinned" IMO.

 

-Larry

 

OK - my two cents...

 

You need to improve the bandwidth of the video in order to draw nice, fat vertical lines. But, the faster you drive the signal, the more noise and corruption that leaks in. That's why some monitors look really good and some don't. It all depends on their bandwidth verses what your computer is sending out. Sometimes, the limited bandwidth of a cheap monitor filters out a lot of nasties, where a good monitor will display them correctly. (and ugly)

(snip...)

[+Stephen]

OK - my two cents...

 

The 130XE (and, I assume, the 65XE) are designed with high current, high speed video and they work pretty well. You would think that just duplicating the XE circuits in a 1200XL, for example, would give you the same, nice video. Try it - it won't. The board itself can't supply the necessary current.

 

Bob

Perhaps a dumb question Bob. Could you increase the current handling capacity of the bad PCBs using thin solid core wire - i.e., doubling up on the traces? Or would it still induce noise due to the extra wiring or bad circuit paths?

 

Stephen Anderson

[+bob1200xl]

Yes, you can improve things by adding wire to the board, actually. Thick wire would be marginally better. Wire and traces on the PCB have a certain amount of inductance to them. An inductor is just the property that results from the creation of the magnetic field that builds up around any conductor with current flowing through it. The less current flowing through each little cross-section of the wire, the less the inductive effect. So, bigger wire means less inductance. (this effect is more pronounced with very small wire whose resistance is also higher)

 

BUT, that would be a hit-and-miss, terribly messy task.

 

What you see designers do is reduce the distance that current must flow and increase the capacity of the board to supply current locally at the pins to the IC. They use capacitors and large, filled areas of the PCB to improve the current supply. PCBs with ground planes are best. The 1450XL PCB has a ground plane and the signals on that board look terrific.

 

The proper solution is to get back into the digital signals and start over with a better, external PCB. Looking at VBXE, that looks like what they do. (although I don't see how the GTIA signal is used - do they generate the whole thing in logic?)

 

Bob

 

 

 

OK - my two cents...

 

The 130XE (and, I assume, the 65XE) are designed with high current, high speed video and they work pretty well. You would think that just duplicating the XE circuits in a 1200XL, for example, would give you the same, nice video. Try it - it won't. The board itself can't supply the necessary current.

 

Bob

Perhaps a dumb question Bob. Could you increase the current handling capacity of the bad PCBs using thin solid core wire - i.e., doubling up on the traces? Or would it still induce noise due to the extra wiring or bad circuit paths?

 

Stephen Anderson

[flashjazzcat]

Yep - this 800XL is crying out for a VBXE. My VBXE lives in the 65XE whose output degraded after I did the Supervideo mod on it. The 800XL, though, seems an even more deserving case.

[flashjazzcat]

Since we were talking about the XE vs XL video circuits, I've been experimenting tonight with various settings on the LG Flatron, and found I could enlarge the image somewhat. Also, the presets make a hell of a difference. The output from an unmodded 130XE (let's not get too carried away!) is not that far off the clarity of the VBXE equipped machine:

 

 

 

I would be loathe to tamper with the stock video circuitry of either of my unmodded XEs. As for the 800XL, the cut-down VBXE idea or RBG-outputting remanufactured GTIA sounds an excellent solution.

Edited December 7, 2009 by flashjazzcat

[+Stephen]

You are really making me want to go get one of those LG televisions! Not sure if there is an NTSC version with RGB in though. That's not a common thing over here.

 

Stephen Anderson

[flashjazzcat]

You are really making me want to go get one of those LG televisions! Not sure if there is an NTSC version with RGB in though. That's not a common thing over here.

If you can find such a thing, get one. I may have just hit lucky with this particular model, though: I don't know. I'm certainly over the moon with the picture I'm getting from stock XEs, after a bit of tweaking.

[+wood_jl]

Happy New Year, everybody.

 

What about NO RESISTOR IN CHROMA?

 

Tonight, I engaged in hamfisted, amateur soldering, so I took out my Walmart equipment and hooked up the chroma line on my Rev.C 800XL. I didn't use a resistor, simply because I did not have one, so I decided to see what it looks like. I have not done any other changes yet.

 

I did it! (yippee, right?) I grabbed my Ebay S-video + composite cable.

 

The colors look kind of dull - the screen is not as bright as the 130XE - the blue screen just seems a little dull. I don't know if I should call it "washed out" or what. In other regards, the definition is equally sharp, and I see no zigzags, and I don't see vertical lines.

 

I took pictures of the 130XE screen and this one, and the camera is unable to resolve the difference, but your eyes can. [i don't know how to photograph CRT with digicam]

 

Using composite, the video looks fine.

 

I don't know beans about electronics, so please forgive the simplistic questions:

 

1) Why is a resistor needed in the chroma line? This procedure calls for 100-ohm, but in ANTIC magazine, VOL. 4, NO. 10 / FEBRUARY 1986 / PAGE 6 - in the "I/O Board" where readers write-in, it says 200-ohm. What would be the difference between using these two?

 

2) Could my disappointing screen be a result of the omission?

 

3) C56 - "remove it completely" means don't put a jumper or anything there - just leave holes? [i told you I don't know anything here]

 

4) R53 - the technique (post #1) talks about having a 390-ohm (orange, white, brown) resistor, solder 100-ohm across it, or if you have a 100-ohm resistor (brown, black, brown) then either leave it alone or solder a 330-ohm resistor across for a small luminance improvement. But mine is neither of those colors. I feel like my eyes are going bad here; I can't tell if this is [bROWN, PINK, RED] or [bROWN, ORANGE, RED] or [bROWN, RED, RED]. Surely they wouldn't use colors so close as pink and red! Can somebody please help identify this? I took 3 pics because NONE seemed ideal.

 

Edit: click on pic to make it bigger. (that's what she said)

 

 

5) Chroma Feedback Resistor: What is a 1K resistor, exactly? I'm guessing this means 1000-ohm but I dont know, and I'm going to have to ask for this somewhere.

 

6) I don't know **anywhere** that stocks this stuff. Radio Shack doesn't look anything like it did 30 years ago; where are all the little component packages supposed to be hanging on the wall? It looks like a small retail outfit. Can somebody recommend an online place to source this stuff, in reasonably small quantities? I wouldn't mind having a few extras, should I be fool enough to try this again.

 

Thanks in advance, for any suggestions you may have. I suppose everybody has to start somewhere. I don't think I'll be performing any RAM upgrades or remove any soldered-in chips, at this point!!!

Edited January 2, 2010 by wood_jl

[Havok69]

To answer at least one question; Radio Shack still does sell some electronic components - you'll just have to tell them you don't want a damn cellphone first. They keep what's left of their slowly disappearing electronic parts in drawers now. Usually these parts drawers are in one of the standalone aisles or they sometimes have a wall on casters they hide it behind. Good luck!

[+bob1200xl]

Google: Jameco

 

They have a 1/4 watt, carbon film resistor kit for $15 (without the cabinet).

 

You will probably overload the CHROMA circuit with no resistor. You can use a capacitor (.001ufd), if you like. Either way, this should fix your 'dull' color.

 

"Reomove it completely" - just leave the holes.

 

The resistors in your pictures are: (top to bottom) 10K (10,000 ohms), 1.2K (1200 ohms), 390 ohms, and 1K (1000 ohms).

 

Bob

 

 

 

 

 

 

 

Happy New Year, everybody.

 

What about NO RESISTOR IN CHROMA?

 

Tonight, I engaged in hamfisted, amateur soldering, so I took out my Walmart equipment and hooked up the chroma line on my Rev.C 800XL. I didn't use a resistor, simply because I did not have one, so I decided to see what it looks like. I have not done any other changes yet.

 

I did it! (yippee, right?) I grabbed my Ebay S-video + composite cable.

 

The colors look kind of dull - the screen is not as bright as the 130XE - the blue screen just seems a little dull. I don't know if I should call it "washed out" or what. In other regards, the definition is equally sharp, and I see no zigzags, and I don't see vertical lines.

 

I took pictures of the 130XE screen and this one, and the camera is unable to resolve the difference, but your eyes can. [i don't know how to photograph CRT with digicam]

 

Using composite, the video looks fine.

 

I don't know beans about electronics, so please forgive the simplistic questions:

 

1) Why is a resistor needed in the chroma line? This procedure calls for 100-ohm, but in ANTIC magazine, VOL. 4, NO. 10 / FEBRUARY 1986 / PAGE 6 - in the "I/O Board" where readers write-in, it says 200-ohm. What would be the difference between using these two?

 

2) Could my disappointing screen be a result of the omission?

 

3) C56 - "remove it completely" means don't put a jumper or anything there - just leave holes? [i told you I don't know anything here]

 

4) R53 - the technique (post #1) talks about having a 390-ohm (orange, white, brown) resistor, solder 100-ohm across it, or if you have a 100-ohm resistor (brown, black, brown) then either leave it alone or solder a 330-ohm resistor across for a small luminance improvement. But mine is neither of those colors. I feel like my eyes are going bad here; I can't tell if this is [bROWN, PINK, RED] or [bROWN, ORANGE, RED] or [bROWN, RED, RED]. Surely they wouldn't use colors so close as pink and red! Can somebody please help identify this? I took 3 pics because NONE seemed ideal.

 

Edit: click on pic to make it bigger. (that's what she said)

 

 

5) Chroma Feedback Resistor: What is a 1K resistor, exactly? I'm guessing this means 1000-ohm but I dont know, and I'm going to have to ask for this somewhere.

 

6) I don't know **anywhere** that stocks this stuff. Radio Shack doesn't look anything like it did 30 years ago; where are all the little component packages supposed to be hanging on the wall? It looks like a small retail outfit. Can somebody recommend an online place to source this stuff, in reasonably small quantities? I wouldn't mind having a few extras, should I be fool enough to try this again.

 

Thanks in advance, for any suggestions you may have. I suppose everybody has to start somewhere. I don't think I'll be performing any RAM upgrades or remove any soldered-in chips, at this point!!!

[rchennau]

I just applied this modification to my 800XL rev D board. It works well. I have faint vertical lines and so I am researching how to remove those. However they faint vertical lines are not as pronounced as is referenced in this topic thread from other mod'ers.

[bobkat2769]

I've got a question related to this topic that I sure could use some help with. There are probably a number of other people with the same problem.

 

I installed the super video upgrade to my two 800XLs a couple of years ago and they look great with an S-video cable I got on ebay.

 

I recently replaced my primary TV from a 10 year old Sony 37" CRT TV to a Sony Bravia KDL-46EX500 after the old one died a few weeks ago. The new TV has no S-video inputs but it does have everything else. That is, it has RF, composite, component, VGA, and HDMI inputs.

 

My problem is as follows:

 

Is there anyway I can cheaply convert the S-video output of my 800XL to component or HDMI for use on the new TV?

 

Thanks much in advance,

 

BobKat =^.^=

[Rybags]

Not really.

 

If you have something like a HDD Recorder with S-Video input, then you could just use that.

[+wood_jl]

I recently replaced my primary TV from a 10 year old Sony 37" CRT TV to a Sony Bravia KDL-46EX500 after the old one died a few weeks ago. The new TV has no S-video inputs but it does have everything else. That is, it has RF, composite, component, VGA, and HDMI inputs.

 

That's one thing about modern SONY products that utterly SUCKS. I have a 35" SONY CRT Trinitron and a SONY DVD player (and everything else) through S-video. When I was looking for a replacement DVD player, I noticed that **all** the SONY brand players now omit the S-video. I simply bought older models (known good SONY model) from Ebay. I'm glad SONY is able to save $1 per unit by omitting the S-video, all the while charging the highest prices of all makers for their products; even the cheapest Emerson and Magnavox DVD players have S-video.

 

It may be the case that other makers have/will eliminate S-video from their modern sets as well, but even if a lowly Vizio (or whatever) is the only brand that has S-video, then a Vizio (or whatever) customer I will be. I find it difficult to remain a SONY customer. This isn't some fanboy rant, mind you, merely an observation of undersirable facts.

 

 

 

Is there anyway I can cheaply convert the S-video output of my 800XL to component or HDMI for use on the new TV?

 

Man, if there was, it would surely save the [future] day.

[Rybags]

S-video is pretty crap in the context of displaying high-def video.]

 

I've got the opposite problem with the Digital Tuner I now use to record stuff... it's only got A/V and S-Video, no Component.

 

Re RGB or component, there was mention of an internal mod that could be developed. Atari has constant colour saturation, so all that needs to be done is to measure the phase delay relative to the master clock.

GTIA outputs digital luma info, so it would be relatively simple for someone with the knowhow to develop something like a cutdown VBXE that could interpret the GTIA signals and output RGB and/or Component.

[flashjazzcat]

Re RGB or component, there was mention of an internal mod that could be developed. Atari has constant colour saturation, so all that needs to be done is to measure the phase delay relative to the master clock.

GTIA outputs digital luma info, so it would be relatively simple for someone with the knowhow to develop something like a cutdown VBXE that could interpret the GTIA signals and output RGB and/or Component.

This would be good to see. No-one can afford to put VBXE in all their machines: a cheap RGB board is a great idea, I feel.

[+bob1200xl]

It's a little more complicated than that, although capturing the video should be fairly easy.

 

You would probably want two frame buffers to store/read the digital data. Output 480p to the monitor.

 

They make clock chips that will sync a 16x clock to the 3.58mhz oscillator and video chips that input digital data and output RGB or component. All the messy stuff is done.

 

I think we'll lose artifacting, though...

 

Bob

 

 

 

 

S-video is pretty crap in the context of displaying high-def video.]

 

I've got the opposite problem with the Digital Tuner I now use to record stuff... it's only got A/V and S-Video, no Component.

 

Re RGB or component, there was mention of an internal mod that could be developed. Atari has constant colour saturation, so all that needs to be done is to measure the phase delay relative to the master clock.

GTIA outputs digital luma info, so it would be relatively simple for someone with the knowhow to develop something like a cutdown VBXE that could interpret the GTIA signals and output RGB and/or Component.

[Rybags]

Yes, 480p would be a must since Amiga monitors and the like are getting rare.

 

But I think the better option there might be to just do line-doubling on the fly so you're just driving the monitor at ~ 31 KHz.

 

Then again, that's probably the preferred NTSC solution since frame-doubling would give 120 Hz frame rate which many monitors won't like.

 

On the other hand, many monitors also don't work so great at 50 Hz PAL rate, so maybe such a product would need to be able to do both methods.

[bobkat2769]

Re RGB or component, there was mention of an internal mod that could be developed. Atari has constant colour saturation, so all that needs to be done is to measure the phase delay relative to the master clock.

GTIA outputs digital luma info, so it would be relatively simple for someone with the knowhow to develop something like a cutdown VBXE that could interpret the GTIA signals and output RGB and/or Component.

This would be good to see. No-one can afford to put VBXE in all their machines: a cheap RGB board is a great idea, I feel.

 

Something like that would be great.

 

For now, I can use the S-video inputs on my Onkyo AV receiver and it will convert to component for me. But in the fairly near future I want to upgrade to a newer Onkyo model. The only problem is that most of the AV receivers I looked at no longer have S-video. They have plenty of different input types, but it seems like S-video is being phased out by nearly all of the manufacturers.

 

For that matter, none of the TVs I looked at had any S-video inputs either. =o.O=;;

 

Anyway, for those who want to know, I am currently using an Onkyo TX-SR604 that I've been very happy with for the past few years. Its a very nice unit but it doesn't support a lot of the newer sound codecs all that well and it definitely doesn't have enough HDMI inputs (only 2) and they're at 1.1. It also won't convert any of the the analog inputs to HDMI.

 

The one I'm considering replacing it with is the Onkyo TX-SR608. It has all the features my current unit has and plenty of HDMI inputs and outputs. It even has THX certification and at about $450 it won't take me too long to save up for it. The only bad point is that it has no S-video at all. I just can't afford to spend $800+ on a decent receiver just to get S-video.

 

I was hoping that someone here might know of a way to modify the 800XL to output component video or know of some kind of adapter unit that translates S-video to component. I don't need it to upscale or anything like that. My current AV receiver, as well as the TV, can do that job just fine. I just don't want to have to go back down to NTSC composite video after getting used to the beautiful output I get with the current S-video.

 

While I'm fairly good with electronics, I'm not good enough to do design work or figure out how to do this on my own. I'm only a fair-to-middling repair tech and a lot of the newer stuff that's come out for consumer electronics in the last 20 years I just don't understand well enough to fix without service data. I do much better fixing PCs and stuff like that. =^.^=;;

 

Anyway, if anyone here can figure out some kind of a basic mod to go from S-video to component I'd be willing to try wiring something up and giving it a try.

 

BobKat =^.^=

[bobkat2769]

If you've done your S-video mod properly you won't have any artifacting at all. That's actually the whole point of going from composite to S-video. =^.^=

 

As to S-video not being any good for HD, that's absolutely correct. So far as I know it was only designed to work with SD video. And it always seemed to me like it was a low-cost compromise for the consumer market.

 

It is certainly far cheaper, and easier to hookup, an S-video connection than it is to implement the (then) current RGB/BNC cabling scheme available back in the 80's and 90's for professional monitors.

 

I'm pretty sure that was one of the major reasons why the component cabling scheme was created as it could handle higher resolutions and still use the much less expensive RCA audio/video cables.

 

Feel free to correct any of the gaps in my knowledge regarding the RBG/BNC scheme. I'm sure there are points I'm forgetting. I never did have much use for that setup. I've always used either S-video, component, or VGA connections when I ran into the RGB/BNC connectors on various equipment. =^.^=;;

 

BobKat

 

It's a little more complicated than that, although capturing the video should be fairly easy.

 

You would probably want two frame buffers to store/read the digital data. Output 480p to the monitor.

 

They make clock chips that will sync a 16x clock to the 3.58mhz oscillator and video chips that input digital data and output RGB or component. All the messy stuff is done.

 

I think we'll lose artifacting, though...

 

Bob

 

S-video is pretty crap in the context of displaying high-def video.]

 

I've got the opposite problem with the Digital Tuner I now use to record stuff... it's only got A/V and S-Video, no Component.

 

Re RGB or component, there was mention of an internal mod that could be developed. Atari has constant colour saturation, so all that needs to be done is to measure the phase delay relative to the master clock.

GTIA outputs digital luma info, so it would be relatively simple for someone with the knowhow to develop something like a cutdown VBXE that could interpret the GTIA signals and output RGB and/or Component.

[flashjazzcat]

I was just looking into this RGB business and realized that producing the RGB output "at source" would require interception of display data at the point ANTIC deals with it, requiring emulation of GTIA a la VBXE. If we tap the video signal off GTIA it's going to be a degraded s-video to RGB conversion.

 

Genuine RGB output is one of VBXE's greatest selling points. No wonder the idea of a "cut down" version didn't appeal much: all the GTIA emulation would still be required, even if the custom graphics modes were jettisonned.

[Rybags]

It can be done by tapping from GTIA... it's just that you need high precision to measure the colour phase, ie around 16 samples per colour clock.

Luma is easy since it's a digital signal at the source.

 

And since saturation is constant, there's no additional calculations needed there. Of course, the ideal convertor would probably have some facility to upload palettes to it, so you could just customise the saturation levels to be what they should really have been, ie less for the darker shades and more for the lighter ones.

[+bob1200xl]

Yes - feed the 8 bits of digital Atari (4 from LUMA and 4 from CHROMA) into an array that would give you 16-24 bits of component or RGB digital data. If you use SRAM for the array, it would have to be loaded at POR, ideally from a flash chip. This would make it easy to load the SRAM array with only hardware and yet allow you to re-write the flash if you wanted a custom scheme. All transparent to the Atari user/software.

 

Bob

 

 

 

It can be done by tapping from GTIA... it's just that you need high precision to measure the colour phase, ie around 16 samples per colour clock.

Luma is easy since it's a digital signal at the source.

 

And since saturation is constant, there's no additional calculations needed there. Of course, the ideal convertor would probably have some facility to upload palettes to it, so you could just customise the saturation levels to be what they should really have been, ie less for the darker shades and more for the lighter ones.