Back in the early 90's when Ben poehland was still in the atari scene and doing the "atari classics" mag he had an article in one issue (I forgot which one) which gave detailed info to do the video upgrade on most of the 8bit line. Luckily a friend in the local user group had a copy he let me read to do a 600XL I had setup for my dad (though for me it was mainly to use composite out for an old monitor rather than better graphics). Unfortunately AC, Ben P, and that user group are long gone and I haven't been in touch with that friend in at least 5 or 6 years
