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Magic Knight

Make your own S-Video for your 8-bit card easily and quickly

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Hi

 

Heres how you can make your own top quality S-Video video board for almost any Atari 8 bit. It uses few parts and would take minutes to install.

 

The Atari series shares the same common IC graphics chip (GTIA) and has Luma and chroma produced at a high level. Unfortunately Atari made an ass of this on the XL series (particularly the 600XL) and didnt improve much with the XE series.

 

I produced a module that did this a few years back but thought i would make the details on how you can make your own here. Ive photographed my own for clarity, but ive some ataris with just the components hard wired on to the boards with wires,

 

The circuit has been tested on:

 

400

800XL

600XL

65XE

130XE

800XE

XEGs

 

it will definitely work on 1200XL's and 800's, however the 800 has good native s-video, so it would be best to leave alone or use Jurgens 800 color board as the components needed to remove are more fiddly.

 

 

Parts required:

 

33 Ohm resistor (any wattage - a 0.25w one is suggested)

50 ohm trimmer

16V 22uF capacitor (10uf value will work also)

 

 

The circuit looks like this (both on cad and in simple layout)

 

post-34640-0-33240200-1547218232.jpg post-34640-0-31763000-1547218264.jpg post-34640-0-90403300-1547218481.jpg

 

 

The layout should be similar to this:

 

post-34640-0-11556900-1547218308.jpg post-34640-0-11230000-1547218572.jpg

 

 

 

The circuit can easily be hard wired together or put on prototype board etc.

 

The instruction on installation to your Atari can be found here (ignore the fact its a module and substitute for the board/circuit) Magic Knights XL-XE module instruction.pdf

 

Anyone wanting to make their own PCB - heres the gerber files etc : XL s-video 1.00f_2018-12-04.zip

 

 

Comments and questions welcome!

 

Richard

Edited by Magic Knight
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Hi, this look great. I have a question though. I have a 600XL with UAV installed that have a nice video output, and a 800XL with chroma mod and a simple mod i don't remember right now (a simple one I got from here: I basically lifted a resistor, as far as I remember), That 800XL also look great in my Dell 2007fp monitor. But When I connect my 65XE (64x4 motherboard) with stock video output the image is totally wrong. I need to decrease the saturation control in the monitor setting to make it look similar to the other ones.

So the question is: Will the variable resistor here will help me adjust the saturation level on this 65XE (130XE motherboard)?

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nice and neat - can you upload a screenshot?

Heres a couple of quickies

 

post-34640-0-36412100-1547231816_thumb.jpg

 

post-34640-0-36045500-1547232285_thumb.jpg

 

Blue screen looks multi shaded but is a single colour as we know graphics 0 cant do that in the flesh! My camera being as it is..

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Hi, this look great. I have a question though. I have a 600XL with UAV installed that have a nice video output, and a 800XL with chroma mod and a simple mod i don't remember right now (a simple one I got from here: I basically lifted a resistor, as far as I remember), That 800XL also look great in my Dell 2007fp monitor. But When I connect my 65XE (64x4 motherboard) with stock video output the image is totally wrong. I need to decrease the saturation control in the monitor setting to make it look similar to the other ones.

So the question is: Will the variable resistor here will help me adjust the saturation level on this 65XE (130XE motherboard)?

If your using the built in gash from the monitor port then theres (probably) not a lot of point trying to manipulate the crippled signal. Having straight off the Gtia is the purest way and straight the horses mouth so to speak.

 

The resistor may help but any noise will still be there. Try a 68 or 75 ohm first to see if it works.

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Blue screen looks multi shaded but is a single colour as we know graphics 0 cant do that in the flesh! My camera being as it is..

 

I don't think that's your camera creating that effect. Looks like a product of TN (twisted nematic) monitors where the top is darker than the bottom. https://www.tnpanel.com/tn-vs-ips-va/ It's normal.

 

Thank you for sharing this video upgrade!!

Edited by Sugarland
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I don't think that's your camera creating that effect. Looks like a product of TN (twisted nematic) monitors where the top is darker than the bottom. https://www.tnpanel.com/tn-vs-ips-va/ It's normal.

 

Thank you for sharing this video upgrade!!

and the lighting source can be moved/ adjusted to minimize the effect on some or those monitors, what a pain... never liked it!

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and the lighting source can be moved/ adjusted to minimize the effect on some or those monitors, what a pain... never liked it!

I still have to use CRT on my real rigs. I gotta say though - PAL flicker is rough on me, living in NTSC land, and being ultra sensitive to flicker even at 60Hz monitors, fluorescent tubes, etc..

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Thanks for releasing the information!

 

Could you please post the installation instructions / modifications for an Atari 400?

 

Thanks!

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Thanks for sharing your design.

Is this PAL/NTSC specific or does it work for both?

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Is this based on the boards KJMann was selling a few years ago?

 

Yes, the installation was incomplete for some models of 8 bits and needed new documentation. Also was surprised this wasnt the norm for s-video out as theres lttle help needed from the Gtia (other than bi-passing Ataris awful handling of the signal).

 

Thanks for sharing your design.

Is this PAL/NTSC specific or does it work for both?

works for both. Just tones down the signal for the monitors- using least qty passive components where only required.

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I still have to use CRT on my real rigs. I gotta say though - PAL flicker is rough on me, living in NTSC land, and being ultra sensitive to flicker even at 60Hz monitors, fluorescent tubes, etc..

 

 

It's funny how we never "noticed" the 50Hz flicker in Europe BITD......we didn't know better !

I do remember noticing it from the corner of my eyes more than when directly looking at it, this is because of the "design" of our eye...movement from the sides is faster detected around the center of our view field because of obvious reasons....

 

Today I run my 600XL in "semi" NTSC mode about 95% of the time because of the the obvious advantages: faster games, 60Hz much steadier on the eye, correct aspect ratio, better colors.

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Today I run my 600XL in "semi" NTSC mode about 95% of the time because of the the obvious advantages: faster games, 60Hz much steadier on the eye, correct aspect ratio, better colors.

 

That's funny, I run my systems 95% of time in PAL mode.

 

I guess sometimes we want what we never had :grin: .

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And what about SECAM computers.

FGTIA has not the same pinout and maybe the board does not have the same component labelling.

 

What are the connection points in a SECAM 800 XL ?

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I am going to give this a shot on my 800. It's true that the 800 has good s-video already, but in my recent experience with my two (admittedly cheap) LCD TV/monitors I only get B/W with either composite or S-video, though it works fine if I put the s-video through my s-video-to-VGA converter (which I want to use with my 1200XL again). I'm hoping using this circuit straight off the 800's GTIA will allow me to get a color signal from my 800 on those cheap TV/monitors; they do work perfectly fine with everything else back to the 1200XL, but the 800's chroma is just a little too old-school for them to handle. At least until I get around to repairing my CBM 1084S CRT, eventually that will be for the 800.

Edited by Gunstar

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And what about SECAM computers.

FGTIA has not the same pinout and maybe the board does not have the same component labelling.

 

What are the connection points in a SECAM 800 XL ?

 

That's a good question on a number of levels. I was asked to fit one of these boards into a SECAM machine a few weeks ago after the computer's owner told me that the board's designer said 'it should work fine' (an assertion reiterated in the installation manual). Fortunately there were other things to do on the machine as well, and as it happened I didn't even attempt to fit the s-video board since everything aside from 'it should work fine' suggested to me that it had no hope of working at all.

 

Firstly, SECAM is not s-video. SECAM delivers both luma and chroma on the same output, but in a way not directly compatible with Composite video (which the s-video board doesn't concern itself with at all anyway). Secondly, even if one wished to add s-video output to a SECAM machine by means of a separate video jack (so one would still have legacy SECAM video on the original jack), nothing about a SECAM system suggests that even that will work, since the colour carrier clock frequency differs from both PAL and NTSC standards. Thirdly, the FGTIA does not necessarily deliver colour information in a way which can hope to be recognised as the chroma component of s-video at the other end of the wire.

 

Nevertheless: it is assumed that it will work. I did not have the heart to even attempt it, but I will happily be proved wrong when I see a SECAM 800XL delivering s-video output with the original GTIA and crystals on-board. :)

Edited by flashjazzcat

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Nevertheless: it is assumed that it will work. I did not have the heart to even attempt it, but I will happily be proved wrong when I see a SECAM 800XL delivering s-video output with the original GTIA and crystals on-board. :)

 

You do not give me so much hope. Maybe Magic Knight will have a working solution (the word Magic in his alias makes me think that he can do everything... pressure pressure!)

 

Generally speaking, I wish there would exist a list of available video mods for SECAM computers.

The only one I tested is the SECAM Sophia board which is EXCELLENT (Thank you very much Simius !)

But there are a bunch of other upgrades which I do not know if they would work with SECAM (Super video 2.1, UAV, this one in the current thread,...)

 

I know that very few people own a SECAM computer, hence the lack of solution for SECAM.

That's funny to see that there are many video mods for PAL / NTSC and that the quality of a stock XL or XE is already good (IMHO) compared to SECAM which is REALLY bad !

So the system which needs the most a video mod has almost no alternative although a video upgrade is a MUST have in SECAM (beleive me!).

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I'll need to take a look at the schematics but it should be do-able.

Any news about SECAM feasability?

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as Jon said above - unlikely that it will be feasible on secam XLs anytime soon.

 

as per the Deck of Cards - "i know, i was that soldier"

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