Marius Posted March 6, 2012 Share Posted March 6, 2012 Hi. I'm not so familiar with Atari 800... I bought one today, but now it appears to be dead. (Green screen). I already cleaned contacts on RAM and OS card. What is the first thing to check when the Atari gives a green screen? Greetz M. Quote Link to comment Share on other sites More sharing options...
candle Posted March 6, 2012 Share Posted March 6, 2012 (edited) 74ls243 & 74ls42 i guess Edited March 6, 2012 by candle Quote Link to comment Share on other sites More sharing options...
Osbo Posted March 7, 2012 Share Posted March 7, 2012 This thread might help you, http://www.atariage.com/forums/topic/177258-atari-800xl-nothing-on-screen/page__st__25 Good luck! Quote Link to comment Share on other sites More sharing options...
Marius Posted March 7, 2012 Author Share Posted March 7, 2012 Thanks for your replies guys. Today I found out that the LS09 on the installed OS-Rom board was dead. Replacing it resulted in a working Atari 800. Still ... this machine is not error free (strange enough). When I switch it on it seeks for Sio hardware (the famous prrrr) but it won't boot from my ABBUC-RAF Sio2USB although that thing gets enough power from the sio port. Strange issues on this computer. It is NTSC btw. It gives a very ugly output on my television (a lot of noise and artifacting) although I use my monitor cable which I also use for my 800XL. I also have a NTSC 1200XL which gives a much better screen output using the same cable and tv. My PAL 800 also gives a perfect screen output through this cable. Is it a common thing that NTSC 800 screen output is worse, or do I have to look further for improving things? Quote Link to comment Share on other sites More sharing options...
Pug Posted January 4, 2021 Share Posted January 4, 2021 Where is the LS09 CHIP? Is it a socketed chip? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted January 4, 2021 Share Posted January 4, 2021 7 minutes ago, Pug said: Where is the LS09 CHIP? Is it a socketed chip? Thanks in advance! That's one of the logic chips on the 800 OS board - a 74LS09 (full designation). That said, a number of things can cause an 800 to fail to boot like this - most common is bad RAM or a bad OS ROM chip. Anyway, the 74LS09 is the socketed chip at bottom-center, just above the card edge connector. Quote Link to comment Share on other sites More sharing options...
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