Years ago, I blew up my NTSCU DC with 240v when I plugged it in whilst absolutely falling-down drunk without the stepdown

Long story short, I got a cheap PAL console from a dealer and used a boot disc to play Japanese and US titles. Thing is, some display correctly, and others badly crop the top and bottom of the screen with ugly borders. Why is this, and is there a workaround (updated boot disk version or some such thing).
Or am I looking at shelling out for a new console?