It took all in all about 3 weeks getting a replacement which I think is simply not acceptable, but at least i got another new 755A.
What is worse though is that my second (out of 4) 755A also have failed me now but with a completely different fault. This drive takes forever writing leadout (making creepy noises), and also scratches the disk, just like the laser is hitting the disk.
I always inspect my disks before putting them in the drives, so I know they were without any scratches before going into the drive.
I use an well cooled, air filtered Antec P180 and high quality components overall, including the PSU. Nothing else has failed me for several years, but these 755A seems like total crap to be honest.
Let's hope the RMA goes quicker this time.