Ok info, using team viewer I entered windows machine who was connected over USB blaster to Vampire 600 V2 card mounted on Amiga. This kind of debugging is fun fun fun
If you think that there is more than 10 000km between us and that you control one machine over another
After investigation I can confirm that connection to the motherboard is good. We were able to write to color register and to run test core without addressed FastRam.
Then each SDRAM chip was tested separately. With U8 system booted but with U7 didn't
1. Bad solder job on that chip
2. Damaged in transport, some pins on that chips disconnected or something like that
3. Dead chip
So, like I told you check each pin on that chip U7 with needle and see do they move. As you have proper equipment if that's the case solder it yourself.
If that's not the case card will be replaced.