Commodore 64 Update. I pulled the PLA from my working C64 and tried it. I still got the black screen. So I dropped in my dead test cart and I started getting memory error codes. I have compatible RAM chips in an old Commodore 128 I scavenged for parts, so I de-soldered 5 of those and started replacing them, I ended up replacing 3 before the memory error codes stopped. Now when I run the dead test, I get normal startup border, but screen full of garbage characters. The tests are running, they are just not displaying properly. At this point, I am thinking it is either the VIC II or the character ROM. My next step is to drop in my VIC II from my other system and see if that makes it work. VIC II's are about $40. If it turns out to be the character ROM, those are only about $10.