BitCortex

OMG you're absolutely right ? The junk I'm seeing is actually correct! In fact, the Altirra emulator shows exactly the same junk when I enable its extended overscan mode (see screenshots below). Fascinating! I'm actually getting a RetroTINK device to improve the 800 image. Hopefully it'll hide the artifacts ? Thanks for responding!

Whoa I just noticed that my "new" 800 has a similar issue. Blue Max has a column of flickering garbage all the way over on the right. Also noticed issues in Ballblazer and H.E.R.O. Other games like Drol and Boulder Dash are perfect. Ordered a new CPU board from B&C. Can't wait to see if it fixes this.