Originally Posted by retrocomputer22
But I have run the Amiga using the composite output, wouldn't that bypass the scan doubler? .
It doesn't matter. The scandoubler could have damaged the chip legs. It happened to me.
You cannot diagnose the Amiga properly while you have stuff on it. As long as you have it connected I'll suspect it. If it does it without it, then we're looking at another problem and your Amiga is faulty for sure.
RAM could be a problem, but besides graphic corruption it could also yield lockups.
After you removed the scandoubler (be careful when doing so) do as emufan says and run MBRTest.
It does look a bit odd to me as if it was failed rendering. When you have RAM problems, more random garbage is rendered instead .