no disk detected after adding a new diskRN10200, Adding Disks

Ok I have fixed this now but its the most bizarre fix ever as this NAS is new and I cant see how this can happen.  The disks are fine, but I wanted to check that the disk were actually connecting to the sata connection and power in the NAS and feel them spin.  So I manually installed the disk without the tray.  I booted and the NAS found the disk and booted as normal.  I then put the disk back into the tray and sloted it back into the NAS and booted and it did not find the disk.  I cant see how this is at all possible unless the NAS had some sort of rough treatment and pushed the sata connectors back but its basically been sitting there never being moved for a year.  To fix this I have put the disk only half way into the tray and pushed it into the NAS to  ensure there was a connection and then followed with the rest of the tray to hold it steady.  This has worked and everything is back to normal.  I then tried installing disk 2 the same way and its now happily syncing.  No idea how this is possible but i will post this solution into the forum incase anyone else ever has the same issue!