Never heard that before (do you have any links to that?). It's possible that was the case under Tramiel (sounds like something that penny-pincher would do..). If true, that should be the case with the 2600 "JR"s as well. Need to check more of those. However, I have 3 (1984) Rev A 7800s here - Two use an AMI and the other a Synertek, so that doesn't appear to have been the case originally. Atari should have had plenty of TIAs in stock by then, with at least 3 different chip manufacturers making TIAs for them, but who knows what happened after Tramiel took over. Whatever inventory Atari had of them might have been thrown out or sold off between 1984-86.