This is a V9 (not v10) PS2 with a Magic 50k chip installed. It plays PS2 originals and backups nicely, as well as homebrew cds, but any PS1 cds cause the problem mentioned in the title. None of the wires are touching each other, and the areas they cross at are separated with tape. The solder points seem to be clean after inspecting them under 10x magnification, but this problem persists. What could the problem be?