Drobo FS hardware failure

Hi there,
I have a 10 year old Drobo FS, always working correctly. But since I’ve not used it for a while and all of the time it was turned off. Now when I turned it on again it’s indicating that I should insert drives (while they are all inserted). Or it started with 1 drive and then the next one, and now all. Also when I insert only 1 drive (a spare one) it will not see the drive at all, always giving a red light. I think it’s a hardware failure of the drive itself.
Now comes my question, if I buy a good working second hand Drobo FS, the same as I have. And when I just replace the drives of the second hand one with all of my drives, will that work? Or do drives always need to be formatted when inserted in a different drobo FS. I’m trying to save my data and I can buy a second hand drobo, only question is, is it worth the 250,- euro.
Thanks, hope someone has had the same experience.