pcrock Posted October 9, 2020 Share Posted October 9, 2020 1 minute ago, batari said: I see the circuit above lacks the 75 ohm series resistor at output, as specified in an example below and present in most video output circuits that I have seen (including the one in the above post). I personally would not leave this out. Thanks friend! I will do the test now! Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 9, 2020 Share Posted October 9, 2020 (edited) 40 minutes ago, batari said: I see the circuit above lacks the 75 ohm series resistor at output, as specified in an example below and present in most video output circuits that I have seen (including the one in the above post). I personally would not leave this out. I added the 75R serie resistor as you recommended and the results (IN CRT) were GREAT!!!!! The vertical awful interferences has disappeared almost completely! The screen is now well more clean than before! The bright is still less than the desireble even with the trimmer setted ro 0K. After added 75R serie resistor, the trimmer acts a lot more!!!!!! In the Led TV I will able to test the device only later at night. I am at the lab now and the Led TV is at home. The serie Resistor changed a lot (to better) the results! Any Idea about the poor bright and dark colors? I am very sure that there are NO errors on the building the circuit. Checked up a lot! I need that the circuit work well in LED TV models. This console will be used only with LED TV. Thanks again friend! Edited October 9, 2020 by pcrock Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 9, 2020 Share Posted October 9, 2020 (edited) Another thing I noticed is that I can't get a red color at all !! The best I can get is something more like brown. I've tried to do the color adjustment but I never get close to the color red. I'm testing at CRT right now. I can never make it look like the emulator. See below both, Stella and real console running the same game at the same time at the same CRT screen. Edited October 9, 2020 by pcrock Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 10, 2020 Share Posted October 10, 2020 (edited) 8 hours ago, pcrock said: I just tested in LED TV. The results were very very very very BAD!!!! ahahahahah I tested both consoles with the same AV cable, same power supply, same LED TV and same cartridges! The one that uses the CD4050 AV mod works very impressive well!!! But the one with the AV mod we are discussing here shows a very poor quality screen with a lot of interferences and ghost. Now I can see that even in CRT tv, the interferences exist (not so bad as in LED screen but it is still there). Below I post the last pics about the AV circuit from the friend Simon.Plata Below I post the issues at LED TV Below I post some Pics from the console using CD4050 AV mod. Very clean, great colors and sharp graphics. If you see any issue in the pics below is from my cellphone camera. Actual graphics is very impressive good! The black Background is very clean with no interferences or noisy issues. If someone have any idea, I really would like to use the circuit from friend Simon.Plata. Thanks Edited October 10, 2020 by pcrock Quote Link to comment Share on other sites More sharing options...
the_crayon_king Posted October 10, 2020 Share Posted October 10, 2020 1 hour ago, pcrock said: I just tested in LED TV. The results were very very very very BAD!!!! ahahahahah I tested both consoles with the same AV cable, same power supply, same LED TV and same cartridges! The one that uses the CD4050 AV mod works very impressive well!!! But the one with the AV mod we are discussing here shows a very poor quality screen with a lot of interferences and ghost. Now I can see that even in CRT tv, the interferences exist (not so bad as in LED screen but it is still there). Below I post the last pics about the AV circuit from the friend Simon.Plata Below I post the issues at LED TV Below I post some Pics from the console using CD4050 AV mod. Very clean, great colors and sharp graphics. If you see any issue in the pics below is from my cellphone camera. Actual graphics is very impressive good! The black Background is very clean with no interferences or noisy issues. If someone have any idea, I really would like to use the circuit from friend Simon.Plata. Thanks Maybe try an output capacitor ? Unless you are making a mistake like summing audio with the video I don't see any other explanation besides maybe a DC offset. Or try using an op amp. I do not trust transistors. https://easyeda.com/hotdog6394/ths7374-universal-video-amp 1 Quote Link to comment Share on other sites More sharing options...
simon.plata Posted October 10, 2020 Author Share Posted October 10, 2020 5 hours ago, pcrock said: I just tested in LED TV. The results were very very very very BAD!!!! ahahahahah I tested both consoles with the same AV cable, same power supply, same LED TV and same cartridges! The one that uses the CD4050 AV mod works very impressive well!!! But the one with the AV mod we are discussing here shows a very poor quality screen with a lot of interferences and ghost. Now I can see that even in CRT tv, the interferences exist (not so bad as in LED screen but it is still there). Below I post the last pics about the AV circuit from the friend Simon.Plata Below I post the issues at LED TV Below I post some Pics from the console using CD4050 AV mod. Very clean, great colors and sharp graphics. If you see any issue in the pics below is from my cellphone camera. Actual graphics is very impressive good! The black Background is very clean with no interferences or noisy issues. If someone have any idea, I really would like to use the circuit from friend Simon.Plata. Thanks @the_crayon_king made a very good point, you could still have audio signal interference. Did you removed ALL the components indicated in the instructions? Otherwise audio signal could still have a path to mix with video. Also, the indicated components needs to be removed in order to leave a clean chroma and luma signal. The RF oscillator is still in place? Or was removed? I believe all the above makes sense because both the mods you referenced as working properly, are taking signals directly from TIA pins. Bests, 1 Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 10, 2020 Share Posted October 10, 2020 @simon.plata @the_crayon_king Thanks for replying!!! About the audio, sure. The first I made before to start the mod I removed transistor, inductor, resistors and caps. Impossible audio to mix with video because audio oscillator no longer exist! Could it be a ntsc system color issue?? Don't know what is the matter. ,,,? Quote Link to comment Share on other sites More sharing options...
the_crayon_king Posted October 10, 2020 Share Posted October 10, 2020 1 hour ago, pcrock said: @simon.plata @the_crayon_king Thanks for replying!!! About the audio, sure. The first I made before to start the mod I removed transistor, inductor, resistors and caps. Impossible audio to mix with video because audio oscillator no longer exist! Could it be a ntsc system color issue?? Don't know what is the matter. ,,,? The buffer based design could remove analog noise on the luma line. However your issue doesn't seem to be "just" noise. The only time I have seen video with so much distortion is if ground is not connected to the AV cable. What about the blank pin ? I have heard if blank is not connected to COL with a 680ohm resistor it can cause issues. You could also try removing chroma from luma; this will tell you if your video issues are from the chroma line. The picture will be in black and white when you do this but it can help when trying to trace down an issue. Lastly, all things being equal try swapping the mods between the consoles. That will tell you if the issue is in the kit or in the console. Good luck. 1 Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 10, 2020 Share Posted October 10, 2020 @the_crayon_king thanks once more. My great interest on this mod is that it takes the video information all ready to use at RF modulator. The CD4050 mod works very well but to build it and install it takes a lot more of time and work. And we must to put and tie the pcb (bigger than the other mod) in some place instead only to soldering in original modulator holes. Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 11, 2020 Share Posted October 11, 2020 Only a curious thing. Found this schematics in the internet. What do you all think??? Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 13, 2020 Share Posted October 13, 2020 Nobody???? An update. I tried a new TIA chip and a new x200 NTSC xtal but the issues remains the same. When I set the color switch to B/W the colors goes off but is still possible to see the interferences. The console appears to be ok. About the mod circuit, all connections is as short as is possible, good ground. I can't understand the reason to all issues. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted October 13, 2020 Share Posted October 13, 2020 On 10/11/2020 at 5:51 PM, pcrock said: Only a curious thing. Found this schematics in the internet. What do you all think??? The biggest problem you might have is to find a FMS6400, as they are apparently obsolete. You can find people that claim to sell them, but whether you get the real thing or not is another question. I guess if you're looking for a fun project to do yourself, it might keep you busy. Otherwise if you're going beyond a simple amplifier, I'd suggest the UAV currently sold by The Brewing Academy, which has a newer technology of encoder as well as a color timing correction to prevent bleeding colors. And it also has both composite and S-video output options. 1 Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 13, 2020 Share Posted October 13, 2020 9 hours ago, ChildOfCv said: The biggest problem you might have is to find a FMS6400, as they are apparently obsolete. You can find people that claim to sell them, but whether you get the real thing or not is another question. I guess if you're looking for a fun project to do yourself, it might keep you busy. Otherwise if you're going beyond a simple amplifier, I'd suggest the UAV currently sold by The Brewing Academy, which has a newer technology of encoder as well as a color timing correction to prevent bleeding colors. And it also has both composite and S-video output options. Thanks for replying friend. I live in Brazil. UAV really appears to be the best choice (and very cheap to most of worldwide money) but unfortunately, due brazilian money currency, the total cost for it plus (cheapest) shipping is very very very expensive . ?? Quote Link to comment Share on other sites More sharing options...
the_crayon_king Posted October 21, 2020 Share Posted October 21, 2020 On 10/13/2020 at 1:22 AM, ChildOfCv said: The biggest problem you might have is to find a FMS6400, as they are apparently obsolete. You can find people that claim to sell them, but whether you get the real thing or not is another question. I guess if you're looking for a fun project to do yourself, it might keep you busy. Otherwise if you're going beyond a simple amplifier, I'd suggest the UAV currently sold by The Brewing Academy, which has a newer technology of encoder as well as a color timing correction to prevent bleeding colors. And it also has both composite and S-video output options. UAV is the best bet. I had thought his goal was to make his own thing from scratch tho. Or possibly he can't get the UAV shipped to his location. The FMS6410 can still be purchased but it is no longer produced AFAIK. If you source a FMS from somewhere other than china then I really doubt it would be fake. Just old stock. 1 Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 23, 2020 Share Posted October 23, 2020 (edited) On 10/13/2020 at 2:22 AM, ChildOfCv said: Last update. Unfortunately I couldn't find the reasons why this simple mod doesn't work well on my console. The screen has a lot of interference and noise. I had to do the 4050 mod. It was the only way that worked well. A pity because it takes a lot of work to build, so I was interested in this simple mod. Now the image is perfect, clean, clear and very beautiful! 74HC4050 is even better than the CD4050. Attached are some pictures of the amazing result. Thanks to all friends who helped me here, especially to the friend @simon.plata who created this post. P.S.--} I still plain to try FMS6400 version if I can get one. Edited October 23, 2020 by pcrock Quote Link to comment Share on other sites More sharing options...
Shawn Posted October 23, 2020 Share Posted October 23, 2020 On 10/10/2020 at 2:20 AM, pcrock said: I just tested in LED TV. The results were very very very very BAD!!!! ahahahahah I tested both consoles with the same AV cable, same power supply, same LED TV and same cartridges! The one that uses the CD4050 AV mod works very impressive well!!! But the one with the AV mod we are discussing here shows a very poor quality screen with a lot of interferences and ghost. Now I can see that even in CRT tv, the interferences exist (not so bad as in LED screen but it is still there). Below I post the last pics about the AV circuit from the friend Simon.Plata Below I post the issues at LED TV You might find different TV's give you different results depending on how they process the signal? 1 Quote Link to comment Share on other sites More sharing options...
pcrock Posted October 23, 2020 Share Posted October 23, 2020 8 hours ago, Shawn said: You might find different TV's give you different results depending on how they process the signal? I did it. Tried on several TV devices, CRT and LED ones but the issues always was there. On CRT TVs the issues was less than in Led TVs but still is there. On led TV the issues was too much!!! Using the 4050 mod at the same TVs devices as did before, all work perfect. All the pictures I posted here was taken using the same TV device. The issues pics and the solved pics are at the same screen device. Quote Link to comment Share on other sites More sharing options...
Anton5 Posted December 29, 2020 Share Posted December 29, 2020 Was the core reason for the blurry distorted Activision text seen in posts #4 and #9 ever figured out? I have the same on a recent A/V mod done to my 4-switch woody. Quote Link to comment Share on other sites More sharing options...
TomelloSoulMan Posted November 26, 2021 Share Posted November 26, 2021 Sorry for revamping this wonderful thread... I've got a PAL 2600 jr with the Ben Heck's simple AV mod (no transistor) and the signal is too weak to use a passive splitter and feed a capture card and my CRT at the same time. Would this mod give enough output to do this? I want to stream some good oldschool playing and don't want to add an active splitter to my already crowded setup. Quote Link to comment Share on other sites More sharing options...
simon.plata Posted November 26, 2021 Author Share Posted November 26, 2021 1 hour ago, TomelloSoulMan said: Sorry for revamping this wonderful thread... I've got a PAL 2600 jr with the Ben Heck's simple AV mod (no transistor) and the signal is too weak to use a passive splitter and feed a capture card and my CRT at the same time. Would this mod give enough output to do this? I want to stream some good oldschool playing and don't want to add an active splitter to my already crowded setup. It should have enough "power" given that the output impedance is matched to 75 Ohm which is the standard for video. So any splitter which works with standard output video, should work with this mod. Quote Link to comment Share on other sites More sharing options...
TomelloSoulMan Posted November 26, 2021 Share Posted November 26, 2021 5 hours ago, simon.plata said: It should have enough "power" given that the output impedance is matched to 75 Ohm which is the standard for video. So any splitter which works with standard output video, should work with this mod. Thanks a lot Simon, i'll definitely test it and post my results here. Not in the short term tho (real life issues). Quote Link to comment Share on other sites More sharing options...
TomelloSoulMan Posted December 15, 2021 Share Posted December 15, 2021 On 11/26/2021 at 3:45 PM, simon.plata said: It should have enough "power" given that the output impedance is matched to 75 Ohm which is the standard for video. So any splitter which works with standard output video, should work with this mod. Ok, so I built the circuit and the image is awesome... Not a simple interference, crisp and clean on my 14" CRT. I briefly tested the splitter thing and it loses brightness when I plug it, not as bad as with the previous mod where it lost even sync, but i couldn't get my USB composite easycap to display any image, even with the console directly plugged in to it. Not thoroughly tested tho, will do some more tests later. Quote Link to comment Share on other sites More sharing options...
simon.plata Posted December 15, 2021 Author Share Posted December 15, 2021 58 minutes ago, TomelloSoulMan said: Ok, so I built the circuit and the image is awesome... Not a simple interference, crisp and clean on my 14" CRT. I briefly tested the splitter thing and it loses brightness when I plug it, not as bad as with the previous mod where it lost even sync, but i couldn't get my USB composite easycap to display any image, even with the console directly plugged in to it. Not thoroughly tested tho, will do some more tests later. Did you built the one stage or the two stage version? With one stage the gain is in the edge, with two stages you may have more room to compensate the coupling lost with more amplitude gain. Quote Link to comment Share on other sites More sharing options...
TomelloSoulMan Posted December 15, 2021 Share Posted December 15, 2021 6 minutes ago, simon.plata said: Did you built the one stage or the two stage version? With one stage the gain is in the edge, with two stages you may have more room to compensate the coupling lost with more amplitude gain. I built the two stage version, doing my best as seen in the pictures... I'm really an electronics newbie but I tested all tracks with a multimeter and all seemed good. I didn't test various values for the trimmer pot, maybe that makes things better. Forgot to mention I installed this on a rev. F PAL Jr. Quote Link to comment Share on other sites More sharing options...
simon.plata Posted December 15, 2021 Author Share Posted December 15, 2021 1 minute ago, TomelloSoulMan said: I built the two stage version, doing my best as seen in the pictures... I'm really an electronics newbie but I tested all tracks with a multimeter and all seemed good. I didn't test various values for the trimmer pot, maybe that makes things better. Forgot to mention I installed this on a rev. F PAL Jr. Excellent, lowering the trimmer value should augmentate the gain until you get the desired image after the splitter. Quote Link to comment Share on other sites More sharing options...
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