How long can HDD survive without power. I have three Samsung HD103SJ HDDs none of them were powered for few years. I took them from RAID 5 array and all of them were functional. Now I tried to make new RAD 5 array but they are death. All of them.
Im not asking about data retention.
I thought maybe some electrolyte capacitor died or some internal batery that helps actuator arm to get in safe position after sudden power off.
Power has nothing to do with the shelf life of a hard drive. A traditional spinning hard drive does not have a battery or a capacitor to park the heads after a power-off. When the drive loses power the heads simply fly off the outer edge of the platter by centrifugal force and land on a set of pads designed for that purpose. It's a product of physics, not electronics.
So the assumption behind your question is invalid. The answer, without addressing the "data retention" aspect of things, is that a drive will survive without power indefinitely, all other things being equal.
