The strange thing goes on...
I found another 2 of these chips. And again: One is working the other not. :-(
So as i told in my last meassge: Chip1 (codename "Yellow") works Chip2 (codename "Brown") does not work Chip3 (codename "Red") works Chip4 (codename "Blue") does not work
Now i have 6 of those chips, 2 are writeable and 4 are not writeable.
BTW: The codenames are given by the color of the wires.