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Fixing 800 video--where to look after GTIA?

800 video gtia

26 replies to this topic

#26 1050 OFFLINE  

1050

    Dragonstomper

  • 904 posts

Posted Fri Oct 20, 2017 12:15 AM

Yep, too easy so that's not it. I'm suspicious of the
ROM eproms now. The old silicon wasn't all that great
back then and large improvements were made since then.

Sam's Photofact at atarimania might help you with
some scope compares too.
http://www.atarimani...uments_3_8.html

RESET line not high enough? Any address activity?
There has got to be some clue somewhere I would
tend to think, best of luck with it. Get back and
let us know - the next guy is already pulling his
hair out.

#27 vputz OFFLINE  

vputz

    Space Invader

  • Topic Starter
  • 14 posts

Posted Mon Oct 30, 2017 7:28 PM

Haha... but in this case, your ROM instinct was right.  We got a whole working 800 (underpackaged, in "media mail", with most of the keys blasted off the keyboard, but they went back on just fine) swapped the personality board and it popped right up.  Not sure which component on the personality board, but that was evidently the bugger.  Always the last place you look.

 

Thanks for the pointer to Sam's!  We had compared the scope traces to the pics in the 800 field service manual and they seemed to hold up, but this seems like a good resource; I'll check it out.  Although I'm probably going to be tapped for some 8-bit retro entertainment for the evening now that it's back up and running :)







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