Data recovery of My Cloud drive?

My 1st gen My Cloud NAS drive died !..
So I want to try to recover the data.

I removed the drive from the enclosure and put it into a USB hard drive dock and connected it to my computer.

I am unable to read the drive.

I tried in my Mac OSX, Windows 10 PC and a Ubuntu Linux PC.

What OS and file system format does the MyCloud drive use ?

I am unable to mount the My Cloud drive in my computers.

The Hard drives are a WD Green 2tb Model # WD20EARX - 00PASB0
And WD Green 3tb WD30EZRS - 11J99B1

I have 2 My Cloud drives that died upon reboot.
They are old 1st Gen My cloud drives. in a Black case same as Mybook.
The PCB show signs of burns from over heating too.
But the PCB’s still work so the problem is with the drives themselves.
I think I need to change the PCB on the drive itself.
Not the networking PCB.