Kjmann Posted May 10, 2013 Share Posted May 10, 2013 Hooray! I just got my first Atari 400 (NTSC) in very good condition! And it works! What a beauty! But what I need is Composite Video. I cannot use S-Video. I'd like to modify as little as possible. Do I really have to cut the two tracks? Magic Knight wrote that it is not necessary for S-Video. Why should it be necessary for Composite? Could you please explain what you did, KJmann? Or did anybody else try Composite without cutting the tracks? Thanks for any answer.... Bern Just connect the Chroma and Luma together and run the chroma signal with NO resistance (Full Strength). Quote Link to comment Share on other sites More sharing options...
biobern Posted May 10, 2013 Share Posted May 10, 2013 Just connect the Chroma and Luma together and run the chroma signal with NO resistance (Full Strength). Thanks, Kjmann. I will try..... Quote Link to comment Share on other sites More sharing options...
mimo Posted May 11, 2013 Share Posted May 11, 2013 Not tried on a 400 yet, but works on xl,xe and 800 Quote Link to comment Share on other sites More sharing options...
biobern Posted May 11, 2013 Share Posted May 11, 2013 I tried it today and it works! The composite signal is acceptable, but not good. The shadows on the screen are much bigger than with the standard composite signal of my 800 XL. Maybe it's cause the luma and chroma signal are unshielded for around 20 cm? Anybody tried to shield them? Quote Link to comment Share on other sites More sharing options...
biobern Posted May 11, 2013 Share Posted May 11, 2013 OK, I tried it with completely shielded luma and chroma cables now and soldered all the components under the aluminium hood. But it's only a very little bit better now. Still shadows, still washed out colors on the screen. Anyway, I think it's not bad idea to do it like this. But a better composite signal would still be appreciated. Check this (sorry for the bad picture): Quote Link to comment Share on other sites More sharing options...
Kjmann Posted May 12, 2013 Share Posted May 12, 2013 OK, I tried it with completely shielded luma and chroma cables now and soldered all the components under the aluminium hood. But it's only a very little bit better now. Still shadows, still washed out colors on the screen. Anyway, I think it's not bad idea to do it like this. But a better composite signal would still be appreciated. Check this (sorry for the bad picture): This Doesn't look Right to me. Let me look at my original Directions. Quote Link to comment Share on other sites More sharing options...
biobern Posted May 12, 2013 Share Posted May 12, 2013 This Doesn't look Right to me. Let me look at my original Directions. The red cable is connected to luma via the 75 ohm resistor and to chroma via the capacitor. Cable shielding is soldered to ground (under the tape). Isn't that right? Quote Link to comment Share on other sites More sharing options...
Kjmann Posted May 12, 2013 Share Posted May 12, 2013 (edited) The red cable is connected to luma via the 75 ohm resistor and to chroma via the capacitor. Cable shielding is soldered to ground (under the tape). Isn't that right? OK the problem is the cap. it MUST be an electrolitic Capacitor and MUST be 22uF. This Should Solve quite a bit of the ghosting problem. Also Did You Cut The Traces that I marked in Picture "B" Never Mind I forgot those were for the switch if you used it. Edited May 12, 2013 by Kjmann Quote Link to comment Share on other sites More sharing options...
biobern Posted May 12, 2013 Share Posted May 12, 2013 OK the problem is the cap. it MUST be an electrolitic Capacitor and MUST be 22uF. This Should Solve quite a bit of the ghosting problem. Really? It is a tantalum capacitor as recommended by "magic knight" at the beginning of this thread (22uF, plus to mainboard). Does an electrolitic capacitor really have a different behaviour? Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 12, 2013 Author Share Posted May 12, 2013 (edited) Really? It is a tantalum capacitor as recommended by "magic knight" at the beginning of this thread (22uF, plus to mainboard). Does an electrolitic capacitor really have a different behaviour? The tantalum capacitor was suggested with S-Video in mind. and are also better capacitors in general. Composite effects are a problem in themselves... Edited May 12, 2013 by Magic Knight Quote Link to comment Share on other sites More sharing options...
Kjmann Posted May 12, 2013 Share Posted May 12, 2013 (edited) I tried tantalum capacitors In the first designs of this upgrade and had bad luck with them. the cap you use needs to be a one way cap also. Edited May 12, 2013 by Kjmann Quote Link to comment Share on other sites More sharing options...
biobern Posted May 12, 2013 Share Posted May 12, 2013 (edited) I just saw in wikipedia that every tantalum capacitor in fact IS electrolitic. But i'll try a conventional old fashion electrolitic capacitor with blue or black color now! Thanks everybody. Edited May 12, 2013 by biobern Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 12, 2013 Author Share Posted May 12, 2013 I tried tantalum capacitors In the first designs of this upgrade and had bad luck with them. the cap you use needs to be a one way cap also. I use polarized kind of tantalum with the + clearly marked and works great, and also electrolitic. Effects may be more sensitive on composite with the signal strength perhaps being different, Quote Link to comment Share on other sites More sharing options...
biobern Posted May 13, 2013 Share Posted May 13, 2013 (edited) Hi kids! I tried it with a conventional electrolytic capacitor now. But the results are not clearly better. Still strong ghosting, still washed out colors (but clearly better than nothing). BTW: I use a (otherwise very good) Sony CRT-Monitor from the 80s. Ghosting seems to be smaller on a modern LCD-TV (but this looks ugly in many ways with old 8 bit computers). If anybody has any ideas for a better solution, I am too willing to try. Edited May 13, 2013 by biobern Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 13, 2013 Author Share Posted May 13, 2013 (edited) Screen Pictures please... i need to see what you are getting and how bad is bad. Ive got composite working on the 400 and its not worse than the 800 and the XL gives out. The usual purple hint on white test, but i dont see ghosting. The colors are not great but composhite is generally poor on A8 (even the 800 despite the excellent S-vid which is). I am using basic/note pad and track and field as testers for this. (T&F for the colorful spread) It would be better if you could bench mark on these or Donkey kong pac man eastern front these are the carts i have that work on my 400 to compare. i dont see much wrong with your wiring - i would check different grounds on the boards - as i discovered that on parts of the XL, the effect varied depending on where the ground was connected. I guess your monitor doesnt do S-vid?? Edited May 13, 2013 by Magic Knight Quote Link to comment Share on other sites More sharing options...
Kjmann Posted May 13, 2013 Share Posted May 13, 2013 (edited) That's a Good Question. Where are you getting the ground from? And yes, Screen shots would help. Edited May 13, 2013 by Kjmann Quote Link to comment Share on other sites More sharing options...
biobern Posted May 14, 2013 Share Posted May 14, 2013 That's a Good Question. Where are you getting the ground from? And yes, Screen shots would help. Luckily, under the black tape is a big fat ground. I tested it: Zero ohms to other grounds. Quote Link to comment Share on other sites More sharing options...
biobern Posted May 14, 2013 Share Posted May 14, 2013 Screen Pictures please... i need to see what you are getting and how bad is bad. Ive got composite working on the 400 and its not worse than the 800 and the XL gives out. The usual purple hint on white test, but i dont see ghosting. The colors are not great but composhite is generally poor on A8 (even the 800 despite the excellent S-vid which is). I am using basic/note pad and track and field as testers for this. (T&F for the colorful spread) It would be better if you could bench mark on these or Donkey kong pac man eastern front these are the carts i have that work on my 400 to compare. i dont see much wrong with your wiring - i would check different grounds on the boards - as i discovered that on parts of the XL, the effect varied depending on where the ground was connected. I guess your monitor doesnt do S-vid?? No, no S-vid on my good old Sony pvm-2010 qm from the 80s! Here are some screenshots of Notepad and Pacman. Thanks again for your help boys! Quote Link to comment Share on other sites More sharing options...
iratasan Posted May 14, 2013 Share Posted May 14, 2013 I still have the kjmann board ready to be installed (see attached pic). I have to mod a 400 PAL version. Which "route" would you suggest? The one from this topic or...?? Any hints/advice is highly appreciated. Carlo Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 14, 2013 Author Share Posted May 14, 2013 I still have the kjmann board ready to be installed (see attached pic). I have to mod a 400 PAL version. Which "route" would you suggest? The one from this topic or...?? Any hints/advice is highly appreciated. Carlo No Instructions with this? Quote Link to comment Share on other sites More sharing options...
iratasan Posted May 14, 2013 Share Posted May 14, 2013 No Instructions with this? Yes, here they are... https://www.dropbox.com/sh/sfw1yfszuw4z4hf/CP8Vxc9c0Q But i am kind confused... Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 14, 2013 Author Share Posted May 14, 2013 @ Bio Bern I will powerup pacman and my note pad and see how your pictures looks compared to my own quick knock up, Looks like you have more ghosting than the pacman game itself.... Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted May 14, 2013 Author Share Posted May 14, 2013 Yes, here they are... https://www.dropbox....z4hf/CP8Vxc9c0Q But i am kind confused... This looks like a S-vid / Composite hybrid. which do you prefer? or are you rigging this up to have the switch over option to have both? Quote Link to comment Share on other sites More sharing options...
8bit-guy Posted May 14, 2013 Share Posted May 14, 2013 (edited) is anyone can help with the mods sound problems on 5200 composite kits i will be more than grateful http://atariage.com/...re-on-the-5200/ please PM ME Edited May 14, 2013 by 8bit-guy Quote Link to comment Share on other sites More sharing options...
biobern Posted May 14, 2013 Share Posted May 14, 2013 @ Bio Bern Looks like you have more ghosting than the pacman game itself.... Yeah right... :-( Quote Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.