The picture quality is excellent too. And no jumping or artefacts.
But I see that picture is allignet to left edge of TV screen. It is normal?
TV is set to Aspect 16:9. On other settings is ot the same. Only 4:3 added wide strip, which move left edge a bit to center.
Did you power the Atari off between puttting the jumper on and off ? I bet the jumper is only read at boot-up but Simius can answer that.
For RGB connecting to a CRT on a Rev.A board you need to open the jumper of interlace. I had it on at first and the display looked OK to me, first tried DK cartridge then Blue Max, wit Blue Max it was really very clear that it was jumping between lines due to the scrolling.
Now, my B&O TVs have something quite special and they can actually display interlaced video but...is there an advantage between interlaced and non-interlaced ?