thom0707 Posted February 17, 2018 Share Posted February 17, 2018 (edited) Hello, I'm looking to solve an issue I am having with my Atari 800. I bought an S-Video cable years ago off of eBay. It produces crisp video on my Atari 800, but the colors seem off. Additionally, bright colors seem to produce a ghosting effect. Please see my attached screenshot of River Raid. I'll also include a screenshot of Basic to show how characters look (A, M, N, and W in particular). Any thoughts on what the problem is? With an RCA cable, I don't get the ghosting effect, but the colors still seem off. I have an 800XL and the colors look fine with this cable. It's been years since I've used these systems, and I never looked closely at the video output until now. EDIT: In Basic, lowering the luminance of the text seems to help with the ghosting issue. Is there any way I can fix this at a hardware level? Thanks in advance! Edited February 17, 2018 by thom0707 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted February 17, 2018 Share Posted February 17, 2018 (edited) Try a different cable, a different CRT, I had a toshiba that did that, it needed a bit of work, the bleeding and tearing was evident on television, and recording as well. Wasn't the computer at all. https://www.repairfaq.org/sam/tvfaq.htm http://www.e-repair.co.uk/tips.htm If you find it's present from other sources hooked up to it, you may have delve into the set/monitor itself, be protected insulated and keep one hand out using fiberglass or plastic tools, check voltages and caps, this requires discharging everything inside the crt to be safe. Eliminating those items it's time to dig into other causes. Edited February 17, 2018 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
1050 Posted February 18, 2018 Share Posted February 18, 2018 EDIT: In Basic, lowering the luminance of the text seems to help with the ghosting issue. Is there any way I can fix this at a hardware level?Sure, you can construct a resistor network to cut back on the level of luminance and/or chroma both. Some insist on a 75 ohm resistor in line to 'match' impedance to the TV/monitor but this is misapplied #Fake News nonsense for RCA type connections in the first place. Make it to be what works but understand that it's probably only going to work with that computer and that monitor both. Change one or the other and the problem may show back up and in reverse this time. 75 ohm inline wouldn't be a bad place to start either. Which doesn't help any with the repeated rumor that it's the only proper fix. It's well known that the output levels of these computers is quite variable, one is way to hot on luminance and the next has chroma just a screaming. Thanks in advance!Most welcome - it's what we do. 1 Quote Link to comment Share on other sites More sharing options...
JR> Posted February 18, 2018 Share Posted February 18, 2018 Could the color differences be due to CTIA vs. GTIA? Do you know which chip your 800 has? Quote Link to comment Share on other sites More sharing options...
BillC Posted February 18, 2018 Share Posted February 18, 2018 Could the color differences be due to CTIA vs. GTIA? Do you know which chip your 800 has? I don't remember any color difference between the CTIA & GTIA, but is has been over 30 years since I have had a CTIA. The GTIA does have more video modes. The color on the Atari computers can be adjusted via a potentiometer. On the 800 this potentiometer is on the CPU card, and can be adjusted through a hole on the back of the RF shield when the cover for the RAM/OS card bay is removed. 1 Quote Link to comment Share on other sites More sharing options...
thom0707 Posted February 19, 2018 Author Share Posted February 19, 2018 Try a different cable, a different CRT, I had a toshiba that did that, it needed a bit of work, the bleeding and tearing was evident on television, and recording as well. Wasn't the computer at all. https://www.repairfaq.org/sam/tvfaq.htm http://www.e-repair.co.uk/tips.htm If you find it's present from other sources hooked up to it, you may have delve into the set/monitor itself, be protected insulated and keep one hand out using fiberglass or plastic tools, check voltages and caps, this requires discharging everything inside the crt to be safe. Eliminating those items it's time to dig into other causes. I found an another screen with an S-Video input. I didn't see the "ghosting" issue as much, but the discoloration was the same. My SNES seems to produce proper colors via S-Video. Could the color differences be due to CTIA vs. GTIA? Do you know which chip your 800 has? I'm not sure. How can I find out? I don't remember any color difference between the CTIA & GTIA, but is has been over 30 years since I have had a CTIA. The GTIA does have more video modes. The color on the Atari computers can be adjusted via a potentiometer. On the 800 this potentiometer is on the CPU card, and can be adjusted through a hole on the back of the RF shield when the cover for the RAM/OS card bay is removed. I'll see if adjusting that potentiometer helps. If so, I'll post before and after pictures. Thanks! Quote Link to comment Share on other sites More sharing options...
1050 Posted February 19, 2018 Share Posted February 19, 2018 Could the color differences be due to CTIA vs. GTIA? Do you know which chip your 800 has? I'm not sure. How can I find out? I'm thinking by the part number on it. https://www.atarimax.com/jindroush.atari.org/achgtia.html When using google for our beloved Atari, I find it best to include Atari in the search term to cut down on worthless hits, but really CTIA wasn't hard to search for... http://www.atarimania.com/documents-atari-400-800-xl-xe-technical-documents_3_8.html http://www.atarimania.com/list_documents_atari-400-800-xl-xe-_8.html Quote Link to comment Share on other sites More sharing options...
JR> Posted February 19, 2018 Share Posted February 19, 2018 I'm not sure. How can I find out? A few methods are mentioned in this thread.... http://atariage.com/forums/topic/80199-atari-800-ctia-or-gtia/?hl=+test%20+for%20+ctia 1 Quote Link to comment Share on other sites More sharing options...
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