Why is the partition of the WD Green 2Tb 3.5" hard drive not detected?

Question

Iron

The hard drive is 2 years old, I use it as an external one, it is divided into 2 sections: 1 TB (let's say F :) and 900 GB (let's say G). The problem started about six months ago, then partition F refused to be detected for the first time and Windows offered me to format it.
In "disk management" it was shown that the file system of the partition was RAW. I solved this problem by running the partition with the command "chkdsk F: / f". Over the next time, the same situation happened a couple more times, but chkdsk rescued me, after which everything worked as if nothing had happened.
A couple of weeks ago, the same story happened, but in the process of checking the partition with the "chkdsk" command, at stage 2 out of 3, an unidentified error came up and the scan stopped. The section is still undecided. After that, I ran the partition again with chkdsk - the same garbage. I tried to scan from under another machine (Before that, a Dell laptop with Win 7), I used HP on Win XP. Ran chkdsk with /f /r flags. nothing changed.
When the disk is idle, the indicator blinks, as if data is being transferred, partition G opens, but the data transfer rate is rather slow - 5 Mb / s versus 30 Mb / s during normal operation of the disk.

Answer 1

scan the entire mhdd screw from under the DOS for readability, and the results will show what to do next

Answer 2

Look at the SMART attributes (for example, the CrystalDiskInfo program) with numbers 5, 197 and 198. If some of them are not 0, then the screw is about to move off, and it's better to backup the info before it's too late.