polyex Posted March 15, 2018 Share Posted March 15, 2018 My Atari 800 (not an XL), is only outputing black and white on both composite and S-Video when hooked to my Commodore 1702, as well as when it is hooked to newer TV's and an older CRT that I tried it on. Interestingly, I am getting color with my Atari 800 on one CRT , an Emerson TV/VCR combo from the 90's, but every other TV in is showing black and white. The Commodore 1702 and the other TV's work fine otherwise and the S-Video input works great on the 1702 with a Commodore 64. I tried adjusting the pot at R309 but I am still getting black and white, whether I am hooked black and white or composite. Anything else I should check? Quote Link to comment Share on other sites More sharing options...
SignGuy81 Posted March 16, 2018 Share Posted March 16, 2018 (edited) Hi, I was just taking a look at some possibilities that may be causing the problem. I would take a look at the transistor array A104, and the 10pF between R196 and pin 12 of A104. The cap itself doesn't show to be labeled with a number on the schematic. Check all the solder joints around that circuit. I would start with those two components first. All I could find for A104 was Atari's part number C010174. I wound up looking up pinouts of other transistor arrays and it appears to me that CA3046(another 14 pin NPN transistor array) has the same pin arrangement as the schematic I'm linking next, not quite sure though if it is a suitable replacement. I'm looking at page 51 of 219 in this PDF http://www.atarimania.com/documents/Atari_400_800_Field_Service_Manual_June_82.pdf Q105 may also be a possibility(over all signal may be weak and why some monitors you hook to are picking up color while others aren't). Q105 is just a common 2N3904 NPN transistor so that may be the easiest to obtain and start off with to try and replace and see if it makes a difference. Edited March 16, 2018 by SignGuy81 1 Quote Link to comment Share on other sites More sharing options...
polyex Posted March 16, 2018 Author Share Posted March 16, 2018 Thanks for your help. I reflowed the solder in that area you mentioned. Did not change anything. I ordered the chip replacement (CA3046) as well as that 2N3904 NPN transistor. Should be here early next week. I will let you know if swapping them out changes things. Quote Link to comment Share on other sites More sharing options...
polyex Posted March 19, 2018 Author Share Posted March 19, 2018 I replaced CA3046 and 2N3904 and even changed the GTIA with a known working one. No change, still getting black and white on S-Video and Composite! Quote Link to comment Share on other sites More sharing options...
Roydea6 Posted March 19, 2018 Share Posted March 19, 2018 I replaced CA3046 and 2N3904 and even changed the GTIA with a known working one. No change, still getting black and white on S-Video and Composite! Is it possible that your Atari 800 is putting a PAL signal when the TV is looking for NTSC video .. Quote Link to comment Share on other sites More sharing options...
polyex Posted March 19, 2018 Author Share Posted March 19, 2018 (edited) Is it possible that your Atari 800 is putting a PAL signal when the TV is looking for NTSC video .. I don't think so. It is supposed to be a USA Atari 800. Where would I check? Edited March 19, 2018 by polyex Quote Link to comment Share on other sites More sharing options...
SignGuy81 Posted March 19, 2018 Share Posted March 19, 2018 Try swapping out A103 also(the 4050 chip), it might be causing the problem as well looking at page 158 of the PDF I linked earlier. Quote Link to comment Share on other sites More sharing options...
+kheller2 Posted March 20, 2018 Share Posted March 20, 2018 My Atari 800 (not an XL), is only outputing black and white on both composite and S-Video when hooked to my Commodore 1702, as well as when it is hooked to newer TV's and an older CRT that I tried it on. Interestingly, I am getting color with my Atari 800 on one CRT , an Emerson TV/VCR combo from the 90's, but every other TV in is showing black and white. The Commodore 1702 and the other TV's work fine otherwise and the S-Video input works great on the 1702 with a Commodore 64. I tried adjusting the pot at R309 but I am still getting black and white, whether I am hooked black and white or composite. Anything else I should check? Are you getting color when using RF?I’m also assuming you know that C64 Has a different pin out so rca cable colors will be different. Quote Link to comment Share on other sites More sharing options...
polyex Posted March 20, 2018 Author Share Posted March 20, 2018 Are you getting color when using RF? I’m also assuming you know that C64 Has a different pin out so rca cable colors will be different. Yes, same problems on RF. I checked the pinout on the Atari with my cable, so I know which is chroma, which is luma and which is audio. The Commodore monitor has seperate plugs for each and I match it to the Atari 800 pinout. It does the same b&w output with composite too. Quote Link to comment Share on other sites More sharing options...
SignGuy81 Posted April 11, 2018 Share Posted April 11, 2018 You may want to take a look here http://atariage.com/forums/topic/277122-early-800-only-showing-bw/ the user found the no color problem with theirs it may be the same issue with yours. Quote Link to comment Share on other sites More sharing options...
adam242 Posted April 12, 2018 Share Posted April 12, 2018 Try swapping out A103 also(the 4050 chip), it might be causing the problem as well looking at page 158 of the PDF I linked earlier. One of my 600XLs had the same problem (no color) and it turned out to be a bad 4050. Quote Link to comment Share on other sites More sharing options...
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