Zane, After erasing thousands of eproms, I have not experienced a maximum ttme. You can try to erase them again. I personally have left eproms under an eraser for days, with no ill effects on the eproms. If another tour under the eraser doesn't work, then you have two bad eproms. Over the years, I made a living replacing defective eproms on telecom equipment. If they do erase, mark them, because my experience tells me they will fail when trying to reprogram. Or they would be a good starting point for board failure troubleshooting and repair. phil