I savaged some 27C4100 and Toshiba TC574200D from Puzzle Bobble boots, but for some strange reason i can't erase them. I left them in the UV eraser for very long yesterday and today i took them with me to work to try on another UV eraser but with the same result. Each time i perform a blank check it always fails the test.
I find strange that all 4 eproms from two different games are all dead.
Anyway, i already bought new ones from evilbay, let's see if that resolves the problem.