PowerEdge 1850 is very old server and it does not support SAS/SATA drives. It only support SCSI drives. Hope this clarifies. You can refer below link for details [URL] 
I have 4x 1850. Yes i know they are old and redundant but they are just for tinkering with.   I am struggling to get hard drives to fit in the caddy. The caddies are yc340. When I put a sas hard drive in them the caddies no longer slide into the bay it is like the hard drive are too wide. Am I missing something? Thanks
Dell 1850 hard disk