70 replies to this topic

[flashjazzcat]

I've written up the s-video mod which has worked quite nicely for me on a couple of XE machines. It's on my projects page here, and this is the direct link to the PDF guide:

UltraVideo XE 1.0 PDF Instructions

I can't repeat often enough that I'm no electronics expert, and anything useful I discover usually comes about by accident. I know one or two people tried the XL version of this mod a while back and got mixed results, so I can't promise things will look as good on your TV as they do on mine. While I'm perfectly happy with the results of the XL mod, I still think the XE could be improved, so hopefully this will be a springboard for knowledgeable people to make further adjustments.

Enjoy!

[atariksi]

flashjazzcat, on Tue Feb 9, 2010 2:00 PM, said:

I've written up the s-video mod which has worked quite nicely for me on a couple of XE machines. It's on my projects page here, and this is the direct link to the PDF guide:

UltraVideo XE 1.0 PDF Instructions

I can't repeat often enough that I'm no electronics expert, and anything useful I discover usually comes about by accident. I know one or two people tried the XL version of this mod a while back and got mixed results, so I can't promise things will look as good on your TV as they do on mine. While I'm perfectly happy with the results of the XL mod, I still think the XE could be improved, so hopefully this will be a springboard for knowledgeable people to make further adjustments.

Enjoy!

What about for NTSC XLs? There must be some simpler connection to enable the chroma line on the monitor jack on NTSC XLs (on one's that don't have one.)

[Rybags]

There is - it's just a length of wire + shrinkwrap covered resistor inline from a point on the board to the monitor jack.

http://www.wolfpup.n.../supervid2.html

Step 7 on that page.

But there's arguments and conflicting information everywhere so far as what resistor value to use.

[atariksi]

Rybags, on Tue Feb 9, 2010 8:08 PM, said:

There is - it's just a length of wire + shrinkwrap covered resistor inline from a point on the board to the monitor jack.

http://www.wolfpup.n.../supervid2.html

Step 7 on that page.

But there's arguments and conflicting information everywhere so far as what resistor value to use.

Yeah, I see I can't use the 100 Ohm resistor-- R66 is being replaced with 75 ohm (from 100 ohm) so if I don't replace that and just want the Chroma pick-off resistor, it can't be 100 ohm.

Weird that Atari had S-video in Atari 800, dropped it in (most) 800XL and then added it back in XE models.

[flashjazzcat]

This version of the mod is for XEs, not XLs. The XL mod assumes the pick-off resistor is already in place. However, it might be best to update the guide with instructions for fitting it.

Edited by flashjazzcat, Wed Feb 10, 2010 5:13 AM.

[puppetmark]

Being snowed in here in the Eastern US, I took some time to play around with this and it seems to improve the video quality on my NTSC machine pretty well. I have one suggestion that seemed to clean things up a little more. I replaced U20 (CD4050B) with a high speed CMOS device M74HC4050. It made the characters a bit more clean on my 40 inch Sharp Aquos. I am not sure why, it may be feeding the TV a better sync tip. I actually got the idea by following Longhorn Engineering's 2600 mods in the 2600 forums.

[flashjazzcat]

puppetmark, on Wed Feb 10, 2010 11:39 AM, said:

Being snowed in here in the Eastern US, I took some time to play around with this and it seems to improve the video quality on my NTSC machine pretty well. I have one suggestion that seemed to clean things up a little more. I replaced U20 (CD4050B) with a high speed CMOS device M74HC4050. It made the characters a bit more clean on my 40 inch Sharp Aquos. I am not sure why, it may be feeding the TV a better sync tip. I actually got the idea by following Longhorn Engineering's 2600 mods in the 2600 forums.

Interesting. Charcter definition is still lacking here too, so it might be nice to include your amendment as part of the mod. Where did you get the HC4050? Can't seem to find one on Farnells, and they're pricey on eBay. Any chance of posting a photo of your improved display?

Oops - found them at Farnells now.

Edited by flashjazzcat, Wed Feb 10, 2010 12:20 PM.

[flashjazzcat]

Puppetmark: your HC4050 idea was right on the money.

My five chips arrived today and I've socketed one in the 130XE:



Though the effect isn't dramatic at first sight, vertical definition is noticably improved. This is particularly apparent when looking at the 80 column display of The Last Word, which was still uncomfortable viewing on both of my modded XEs prior to the 4050 being installed:





Very happy with this - certainly the best s-video picture I've obtained from the XEs. Will be interesting to see if it improves the already superb XL picture.

I'll probably update UltraVideo XE to include this amendment.

[flashjazzcat]

Turning up the noise reduction and sharpness on the unceasingly awesome LG M226WD really improves things even more:

[tregare]

puppetmark, on Wed Feb 10, 2010 11:39 AM, said:

Being snowed in here in the Eastern US, I took some time to play around with this and it seems to improve the video quality on my NTSC machine pretty well. I have one suggestion that seemed to clean things up a little more. I replaced U20 (CD4050B) with a high speed CMOS device M74HC4050. It made the characters a bit more clean on my 40 inch Sharp Aquos. I am not sure why, it may be feeding the TV a better sync tip. I actually got the idea by following Longhorn Engineering's 2600 mods in the 2600 forums.

just be forewarned that HC parts are not designed for TTL input/loads, you might be better off with a HCT part if you can get it, HC are designed for CMOS inputs. also if you are going for speed of chip, an AC/ACT chip with be faster than HC/HCT

[puppetmark]

flashjazzcat, on Tue Feb 16, 2010 12:13 PM, said:

Turning up the noise reduction and sharpness on the unceasingly awesome LG M226WD really improves things even more:

Looks great. I am glad I could contribute a little. tregare makes a good point about the HCT, ACT devices. I had HC parts on hand, so that's what I used but HCT or ACT would probably be a better choice but IMHO, I don't think the loads will kill the HC4050. Time will tell I am sure.

[tregare]

puppetmark, on Tue Feb 16, 2010 3:22 PM, said:

flashjazzcat, on Tue Feb 16, 2010 12:13 PM, said:

Turning up the noise reduction and sharpness on the unceasingly awesome LG M226WD really improves things even more:

Looks great. I am glad I could contribute a little. tregare makes a good point about the HCT, ACT devices. I had HC parts on hand, so that's what I used but HCT or ACT would probably be a better choice but IMHO, I don't think the loads will kill the HC4050. Time will tell I am sure.

I have been re-educating myself on circuit design lately. eventually I will be making a xf551 clone controller but am currently designing a SRAM based indus ramcharger circuit board (the learning curve on some of the PCB software out there is a little steep). but I am no longer patient enough or steady of hand enough to lay out a double-sided circuit board by hand.

Edited by tregare, Tue Feb 16, 2010 9:17 PM.

[flashjazzcat]

I need to educate myself on circuit design, because I know squat about it, but I'd like to learn.

My XEGS arrived this morning (), and I'm going to hunt down the luma/chroma hookup points and fit a 5-pin din monitor port as the first job. Composite output is predictably crap.

On a related note, when I went to plug in the RCA connector on the back of the TV, I noticed I'd left the composite jack plugged in when testing the 130XE. When I'd finished testing the XEGS, I tried the 130XE again, leaving the composite plug out this time. The picture's even better. I feel like I want to invite the neighbours round to have a look, or alert the media. Then I tried the 65XE, which has had exactly the same mods applied to it as the 130XE, but the 65XE still has vertical bars. Just shows they're all different.

Still, the 130XE is unsurpassable now, so it's a good result.

Edited by flashjazzcat, Wed Feb 17, 2010 5:30 AM.

[bob1200xl]

Have you tried ExpressPCB? Their s/w is pretty intuitive, although you can only use it for boards they make for you. I've had good luck with them.

Bob

tregare, on Tue Feb 16, 2010 9:16 PM, said:

puppetmark, on Tue Feb 16, 2010 3:22 PM, said:

flashjazzcat, on Tue Feb 16, 2010 12:13 PM, said:

Turning up the noise reduction and sharpness on the unceasingly awesome LG M226WD really improves things even more:

Looks great. I am glad I could contribute a little. tregare makes a good point about the HCT, ACT devices. I had HC parts on hand, so that's what I used but HCT or ACT would probably be a better choice but IMHO, I don't think the loads will kill the HC4050. Time will tell I am sure.

I have been re-educating myself on circuit design lately. eventually I will be making a xf551 clone controller but am currently designing a SRAM based indus ramcharger circuit board (the learning curve on some of the PCB software out there is a little steep). but I am no longer patient enough or steady of hand enough to lay out a double-sided circuit board by hand.

[Mathy]

Hello Jon

Years ago, I looked at the video circuit on the XEGS because I was interested in the Super Video upgrades (by The Alchemist). And found out that the XEGS's video circuit's got different errors in them then the XE's video circuit. So what works in the XE might not work in the XEGS if you don't fix the problems in the XEGS first.

greetings

Mathy

[flashjazzcat]

bob1200xl, on Wed Feb 17, 2010 9:34 AM, said:

Have you tried ExpressPCB? Their s/w is pretty intuitive, although you can only use it for boards they make for you. I've had good luck with them.

Bob

Heard about it, but not had a look yet. My friend and I were both looking for PCB prototyping software, so I'll certainly check it out.

Mathy, on Wed Feb 17, 2010 6:42 PM, said:

Hello Jon

Years ago, I looked at the video circuit on the XEGS because I was interested in the Super Video upgrades (by The Alchemist). And found out that the XEGS's video circuit's got different errors in them then the XE's video circuit. So what works in the XE might not work in the XEGS if you don't fix the problems in the XEGS first.

greetings

Mathy

I have no doubt about that. I aim to fit a DIN and pick-offs before judging the stock output. Do you know the pick-off locations for jumpers off the top of your head? I was assuming I'd be able to deduce them by relating them to a schematic of the XE circuit.

[flashjazzcat]

Anyone tell me where the hookup points are for chroma/luma on the XEGS? I can't find a circuit diagram anywhere, and the circuit looks radically different from the XE. The RF modulator only seems to have pins for composite, audio and ground.

EDIT: Found it.

Edited by flashjazzcat, Thu Feb 18, 2010 6:08 AM.

[Rybags]

I think these are the XEGS Schematics - the 15-pin keyboard connector is in there, which isn't in any other system.

 xesys.zip   92.5K   167 downloads

[flashjazzcat]

Rybags, on Thu Feb 18, 2010 6:38 AM, said:

I think these are the XEGS Schematics - the 15-pin keyboard connector is in there, which isn't in any other system.

xesys.zip

Thanks! For the record, this is what I found in another thread (which I've since lost track of):

 Super_Video_S_video_for_the_XEGM.pdf   552.79K   272 downloads

[flashjazzcat]

Blast! My Antex soldering iron's died. Don't think I'll be able to get a replacement till next week, so I'll have to go a couple of days without tinkering.

[puppetmark]

flashjazzcat, on Thu Feb 18, 2010 8:11 AM, said:

Rybags, on Thu Feb 18, 2010 6:38 AM, said:

I think these are the XEGS Schematics - the 15-pin keyboard connector is in there, which isn't in any other system.

xesys.zip

Thanks! For the record, this is what I found in another thread (which I've since lost track of):

 Super_Video_S_video_for_the_XEGM.pdf   552.79K   272 downloads

That's my mod. I think it works pretty well, if I do say so myself. Let me know if I can be of help with it. BTW, I just replaced the 4050 with a HCT4050, and it helps with the sharpness on the XEGS too. I should probably add that to the doc.

[flashjazzcat]

Nice mod! So far I've just installed the luma/chroma hook-ups as per your instructions (the iron's working again), but the picture was overdriving the screen pretty badly. The old "eBay" cable and - subsequently - a diode connected in series to the 75Ohm resistor on the chroma pin got the picture to a very acceptable standard. I haven't implemented the rest of your mods yet. I expect the first thing I'll do is isolate the luma/chroma circuits (disabling the composite video), since I suspect that will dramatically reduce the remaining vertical banding as usual. Good tip about the HC4050: thanks!

Edited by flashjazzcat, Sat Feb 20, 2010 2:48 AM.

[w1k]

next week i try this upgrade..

[w1k]

so.. dad make it, but i have black screen..

[w1k]

so.. dad make it, but i have black screen..
i use clasic scart cable

Attached Thumbnails

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Edited by w1k, Sat Mar 6, 2010 6:24 AM.