Ok to make things short, i replaced mainboard and cpu and powered on my system.
One molex was loose on a scsi disk, the controller signaled a cable issue. We powered the system off and checked all connections.
Then the cable error was gone but the drive is marked as failed. It is part of a 2-drives stripe so it cannot be rebuilt, checked, etc. Nada.
The only option is to force it ONLINE.
Inspecting the disk it says that it has no errors, neither physical nor "other".
Now I have the power cable unplugged to "reset" the controller memory. I wonder what could have happened. After fixing the cables, the drive should have been marked online?
The manual is absolutely worthless for troubleshooting. The controller model is a PERC 4/i (equal to lsi 320-2E). And it works perfectly with my mainboard (i was falsely worried).
What to do?