is my NEC defect?
Maybe you have a bad batch of disks? One of the Tyg02 scans looks pretty good, basically what I would expect. Did you check if DMA was enabled?
Is this how your drive has burned from the beginning or where burns better in the past?
You cannot compare this scans, you have to scan the disks at the same speed, 5x or 8x, other speeds seem to work not so good. Your 5x scans donÂ´t look so bad, you can also do some transfer test @13x to contrast with quality scans...