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1200XL - Clearpic or SuperVideo 2.1?

Favored 1200XL Video Mod  

27 members have voted

  1. 1. Which is the preferred video upgrade for the 1200XL?

    • Clearpic Upgrade
      6
    • SuperVideo 2.1
      16
    • Other (specify)
      5


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The Super Video 2.1 was written before ClearPIC2002. Does anyone have a back to back comparison between this and the ClearPic2002? I've never accomplished the Super Video 2.1, but I've upgraded a dozen 1200XLs with ClearPic2002. The results are awesome. The quality of the ClearPic2002 is equal to or better than the original 800.

I think you answered your own question; the 800 has better video than other Atari 8-bits, yet it was also before XL's and XE's. But I'll clarify anyway, newer does not necessarily mean better, especially with the unique 1200XL video.

 

Oops, just noticed I already quoted and replied to this earlier...

Edited by Gunstar

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Would the SV mod work/make sense for a 1200XL that‘s destined for a PAL conversion?

 

 

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After many attempts at making a simple, effective video 'fix' for the 1200XL, I have come to believe that simple is best. The UAV is said to be the absolute best, but it adds a board to the system. This may interfere or conflict with other modifications. Many trials give high bandwidth displays, but some of the 'junk' in the video is best not seen.

 

My mod of choice is to replace R63, L15, and C115 with a wire, and add a wire from the emitter of Q8 to the CHROMA pin of J5. On my monitor (an MJ-22), in separate CHROMA, it looks great.

 

Your monitor may not look as good.

 

This leaves the CHROMA boost circuit in place.

 

All of these mods only work on a 1200XL.

 

You should correct the LUMA, as above, on a PAL system.

 

Bob

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One more thing...

 

I connect the COMPOSITE signal to the CHROMA input of my monitor so I can maintain the s-video even on systems with no CHROMA signal (un-modified 1200XLs and 800XLs).

 

That way, I don't have to move plugs around when I change systems.

 

Bob

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My mod of choice is to replace R63, L15, and C115 with a wire, and add a wire from the emitter of Q8 to the CHROMA pin of J5. On my monitor (an MJ-22), in separate CHROMA, it looks great.

 

Bob

A Teknika MJ-22. I used to have two back in the day. Great monitors. I parted with mine in 2004, when I was stupid and sold all my Atari hardware on eBay.

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Would the SV mod work/make sense for a 1200XL that‘s destined for a PAL conversion?

 

 

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If you look at my signature below, you will see mine is a 100% converted PAL 1200XL with SV 2,1. (Warp OS 32-in-1 includes PAL OS's)This is about the quality of the output video signal regardless of region/

Edited by Gunstar
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This leaves the CHROMA boost circuit in place.

 

 

But does it repair the chroma boost circuit that Atari bungled like SV 2.1 does? Though regardless, this would mean that the repair of the chroma boost circuit from SV 2.1 could be incorporated into your mod.

Edited by Gunstar

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It does not do anything to the CHROMA 'boost', although the CHROMA pick-off is different than the COMPOSITE circuit.

 

Bob

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It does not do anything to the CHROMA 'boost', although the CHROMA pick-off is different than the COMPOSITE circuit.

 

Bob

So does ClearPic2002 take advantage of the chroma boost? It would be hard for me to imagine the picture improving from ClearPic2002.

Edited by ACML

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ClearPic2002 bypasses the CHROMA boost circuits.

 

I don't think the fooling around that Atari did with the CHROMA circuits did much of anything for the monitor outputs. It really only makes sense on the RF output.

 

Bob

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If you look at my signature below, you will see mine is a 100% converted PAL 1200XL with SV 2,1. (Warp OS 32-in-1 includes PAL OS's)This is about the quality of the output video signal regardless of region/

Sorry, rarely read those ;) Thanks for the pointer, this is good news. I read up on the mod details and while it's really quite extensive it seems doable for me.

 

As the article states that you can't observe the difference the CV disable switch makes on a colour monitor, can it be omitted. I doubt I'll ever find a monochrome monitor and if I find one, I'd rather hook it up to an XEP80 or Bit3 (should I ever get hold of the latter).

 

The article also instructs to twist together two 150 Ohm resistors to get 75 Ohms. Is that because there is no 75 Ohm resistor in the kit that's mentioned or does using two in parallel make any beneficial difference electronically?

 

Finally, I have some early revision UAV video mod boards at hand. I gather that SV 2.1 is preferable to UAV?

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Sorry, rarely read those ;) Thanks for the pointer, this is good news. I read up on the mod details and while it's really quite extensive it seems doable for me.

 

As the article states that you can't observe the difference the CV disable switch makes on a colour monitor, can it be omitted. I doubt I'll ever find a monochrome monitor and if I find one, I'd rather hook it up to an XEP80 or Bit3 (should I ever get hold of the latter).

 

The article also instructs to twist together two 150 Ohm resistors to get 75 Ohms. Is that because there is no 75 Ohm resistor in the kit that's mentioned or does using two in parallel make any beneficial difference electronically?

 

Finally, I have some early revision UAV video mod boards at hand. I gather that SV 2.1 is preferable to UAV?

75 ohms is not a standard resistor value, the closest are 68 and 82 ohm. BITD some specialty electronics stores did carry them, but they weren't common.

 

I bought a bag of 100 carbon film 75 ohm resistors for $2 in the late 80's at RP Electronics. At the time it was just a small local shop, it has since moved to a larger location and also added a website. They still sell bulk packs of 75 ohm resistors for under $2.

https://www.rpelectronics.com/cf-1-4-75-75-ohm-1-4w-pkg-100.html

 

These days 75 ohm resistors are readily available via the internet.

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As the article states that you can't observe the difference the CV disable switch makes on a colour monitor, can it be omitted. I doubt I'll ever find a monochrome monitor and if I find one, I'd rather hook it up to an XEP80 or Bit3 (should I ever get hold of the latter).

 

 

 

Either you miss read that or it's an article typo, because I can see the difference in the quality of my color S-video (chroma/luma) change when I flick the composite on/off switch I have. If you are running composite video, then the color will go off and you are left with only the B/W luma signal, which is sharper for B/W or green/amber screens. The reason to keep the switch is to use composite out for games that use color NTSC artifacting for high res programs that make use of it.but still have a perfectly clear non-artifacting S-video output when it is turned off, with it on, it's not perfectly sharp and clear, there is composite signal bleed-over.

Edited by Gunstar

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Ok, got it. So the composite signal when not disabled, I.e. stripped of its chroma part, bleeds into the S-Video output.

 

Did you remove the RF modulator and use the channel switch for this?

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I have attempted to use the channel switch to turn composite on and off but that switch is just not very reliable so I prefer to add a toggle switch to do the job.

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two 150 ohm resistors in parallel will yield 75 ohms there are many ways to get there.... people pick the next closest which is how we end up needing to fix stuff like this in the first place... close enough, close enough, and close enough again sometimes creates very undesirable votes

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Ok, got it. So the composite signal when not disabled, I.e. stripped of its chroma part, bleeds into the S-Video output.

 

Did you remove the RF modulator and use the channel switch for this?

I did, and it has been 100% reliable for me re-purposing the channel switch for this purpose. No need for me to drill an extra hole for a toggle switch in my beautiful 1200XL case . I use the RF out hole for my stereo headphone jack.

post-149-0-18689300-1512449246_thumb.jpg

Edited by Gunstar

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On 12/4/2017 at 9:36 PM, Gunstar said:

I did, and it has been 100% reliable for me re-purposing the channel switch for this purpose. No need for me to drill an extra hole for a toggle switch in my beautiful 1200XL case . I use the RF out hole for my stereo headphone jack.

post-149-0-18689300-1512449246_thumb.jpg

As posted in another thread, I just acquired a 1200XL and the video is a bit meh.  The Chroma I believe is still not connected up.  But at least now I think I have all the parts I need to do the mod.  Still haven't figured out what that switch on the side is for though!  The Rambo XL in it seems to work at least, and I fixed the mylar by ripping out the stupid tape between it and the keyboard.

 

I'll probably attempt the SV2.1 over the weekend, do the instructions here for it show how to utilize the switch to make sure the standard Composite out works?  I am going to start making a list of games that require artifacting to look correct soonish.  I already know Lode Runner, and at least Ultima 3 and 4 do.

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10 hours ago, leech said:

As posted in another thread, I just acquired a 1200XL and the video is a bit meh.  The Chroma I believe is still not connected up.  But at least now I think I have all the parts I need to do the mod.  Still haven't figured out what that switch on the side is for though!  The Rambo XL in it seems to work at least, and I fixed the mylar by ripping out the stupid tape between it and the keyboard.

 

I'll probably attempt the SV2.1 over the weekend, do the instructions here for it show how to utilize the switch to make sure the standard Composite out works?  I am going to start making a list of games that require artifacting to look correct soonish.  I already know Lode Runner, and at least Ultima 3 and 4 do.

If you are asking if the SV 2.1 upgrade, 1200XL version, tells where to hook up the switch to turn composite on and off, yes. You decide where to mount the switch. Since I removed the RF modulator from my 1200XL when I did the SV 2.1 upgrade, I re-purposed the channel selector switch by isolating it from the rest of the board and running wires to it from the point where the composite switch connects on the video circuit.

 

If you are thinking about re-purposing that switch that you can't figure out what it is for, yes, that would work, but you better make sure it isn't needed for something else that YOU need. I used to have an original Rambo in one of my 1200XL's as well as a clone version from Atarimax and I never needed a switch for them, on the original you set jumpers depending on the XL model, but once done it never needs to be switched unless it's removed and installed in anther machine. So I don't see why or how the switch would be for it. If it's still the original 2x24-pin OS roms in your 1200XL then it's not for switching OS's either.

 

IIRC, it also has you connect the missing chroma line in those directions, though I had already done that previously when I did the SV 2.1 mod.

Edited by Gunstar

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I recently attempted the SV 2.1 on a 1200XL and somehow managed to botch it up.  I couldn't get a video signal at all so I inserted a UAV to sweep my errors under the rug.  I have another that I plan to try once more to perform the mod correctly. When I do that I will remove the RF and use that hole for the Composite cut-off switch and use the channel switch to allow for a two OS (XL and Omniview) configuration.

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10 hours ago, hueyjones70 said:

I recently attempted the SV 2.1 on a 1200XL and somehow managed to botch it up.  I couldn't get a video signal at all so I inserted a UAV to sweep my errors under the rug.  I have another that I plan to try once more to perform the mod correctly. When I do that I will remove the RF and use that hole for the Composite cut-off switch and use the channel switch to allow for a two OS (XL and Omniview) configuration.

How did the UAV turn out?  I'm curious why you would do either of the component-by-component mods again when the UAV is (usually) so good?

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The UAV worked out great. I guess prefer the component by component method for the same reasons a person would choose to make a cake from scratch instead of using a mix. Another reason is that I usually buy these computers on eBay, refurbish, modify, repair, and upgrade them for resale. The cost of the components is probably less than $5 and I can resell them for less and still make enough profit to indulge my hobby.

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21 hours ago, hueyjones70 said:

I recently attempted the SV 2.1 on a 1200XL and somehow managed to botch it up.  I couldn't get a video signal at all so I inserted a UAV to sweep my errors under the rug.  I have another that I plan to try once more to perform the mod correctly. When I do that I will remove the RF and use that hole for the Composite cut-off switch and use the channel switch to allow for a two OS (XL and Omniview) configuration.

I liked your post. I was going to do a sad or confused as per your SV 2.1 issues, but then you might think I'm frowning on a UAV, which I'm not. I still use the SV 2,1 S-video out to the Ambery VGA converter and love it. I changed out a resister in my 800's luma circuit which gives me nearly the same quality out as the 1200XL, but most notably the colors aren't as rich. So I'm about to install the Sophia 2 in it, and use RGB out, and if I ever need it to be VGA, I have another RGBtoVGA Ambery converter which works wonderful with my Jaguar and Genesis. Anyway, I'm glad you sorted it with a UAV. Once my Sophia 2 is installed, I'll compare the final output quality between both of my computers and post pictures.

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Two weeks ago I attempted the SV 2.1 upgrade on a 1200XL and when I finished, I could not get any video, no luma, no composite, no chroma.  I checked all my work for solder bridges, missed components etc and found nothing so I installed a UAV.  This week I started on another 1200XL and I went component by component and checked the video after every component.  Initially, I lost video when I removed CR20 so I replaced it.  I lost video again when I replaced R23 (180 OHM) with a 75 OHM resistor.  (The mod calls for a 120 OHM piggyback but the result of that would be 72 OHM)  I thought maybe if I finished the mod, the video would come back but it never did.  I then removed the 75 OHM and replaced it with a 200 (I don't have any 180s) and I got video back.  It is lousy video.  I am going to recheck my components to make sure that I didn't use an incorrect resistor somewhere.  Is anyone aware of any mistakes that were made in the written instructions.  I have successfully done this mod before but it has been several years.  

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