Checking disks from RAID?

Question

Hard disks

Given: an old server with a 3ware 9500 RAID controller, FreeBSD 8, RAID 50 of 5 old Barracuda 7200.8 400 GB + 1 Barracuda 7200.10 500 GB, they have one UFS partition.
Some time ago, some reading errors appeared, the FS was spontaneously unmounted.
fsck_ffs constantly finds errors. Checking by means of the controller gave nothing.
I would like to identify a buggy disk.
Victoria correctly reads SMART - there seems to be nothing criminal. And when checking the surface of any of the six disks, it swears for each sector - as I understand it, this is due to the fact that the disks are marked in RAID (?). Are there any other ways to check the surface?
PS yes, I know it's better to throw out this rubbish and put on new discs. We will assume that I save budget money.

Answer 1

We take out the disks one by one, and scan on another computer with the same MHDD.

Answer 2

I figured it out myself:
It is necessary to remove the ATA password before checking the sectors. For Seagate, this is the word Seagate and 25 spaces.