jcbstein Posted June 19, 2019 Share Posted June 19, 2019 I recently acquired a 600Xl with what appears to be a 48K upgrade (see photo). If I boot to basic I get 1 line displaying garbled information(see photo). If I boot to a dos disk I get a full screen of garbled information (see photo). If I Boot holding option down I get the system test screen displayed properly (see photo). If I load a basic cart. I get the same 1 line of garbled information but if I load a game cart. it loads and runs fine. What might be causing this? Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted June 19, 2019 Share Posted June 19, 2019 48K? seems a bit short, should be 52k to 64k, I'd redo the upgrade install and make sure it's a 64k or greater memory upgrade. The two chips cost next to nothing these days Quote Link to comment Share on other sites More sharing options...
xrbrevin Posted June 19, 2019 Share Posted June 19, 2019 you ought to test the ram using a dedicated program like shortest or xram - the built-in one only goes up to 48k. your machine may well already be 64k Quote Link to comment Share on other sites More sharing options...
Rybags Posted June 20, 2019 Share Posted June 20, 2019 It actually does seem to be 48K - is that really 2 sets of 3 chips stacked on top of each other? It's a right old rats nest there, especially considering the common and easy 64K upgrade involves nothing near the amount of complexity. My suspicion would be that you've got one or more bad or intermittent connections which would be a right pain to diagnose. If it was mine I'd be getting hold of the 600XL to 64K instructions and 2 x 4464 DRams then remove that mess and do the other mod. 2 Quote Link to comment Share on other sites More sharing options...
xrbrevin Posted June 20, 2019 Share Posted June 20, 2019 (edited) i agree, remove the convoluted mess and do the approved 64k method. its much neater and is 100% compatible. https://www.aliexpress.com/item/32855665667.html?shortkey=NzIvyQvY&addresstype=600 do you have another atari you can use to test the various ICs? Edited June 20, 2019 by xrbrevin Quote Link to comment Share on other sites More sharing options...
shoestring Posted June 20, 2019 Share Posted June 20, 2019 You only need 3 wires. http://www.mathyvannisselroy.nl/xl600k64.htm 1 Quote Link to comment Share on other sites More sharing options...
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