HDD head movement sounds in optibay?

Question

Hard disks

I put an SSD instead of a regular HDD, which I plugged into the optibey.
Installed macOS Sierra on SSD. The HDD was disabled and could not be damaged in any way. But after connecting, I noticed annoying sounds even with harmless scrolling of the site pages. Pressing the keyboard keys is also accompanied by sign language translation from the sounds in the HDD. What could it be and how to fix it? Previously, there was no such thing.
The sound is similar to a staccato Morse like buzzing if there is the slightest access to the HDD.