Sounds as if the drive has failed. The fact that you are failing to get any indication on two machines is also an indicator.
You could try opening the caddy up and checking connections and even using a dock for the bare drive to confirm this.
This thread is now locked and can not be replied to.
Sony Vaio Z Canvas release date, price and specs: Another Surface Pro rival but for the US
1995-2015: How technology has changed the world in 20 years
Adobe unveils Sketch-rival Project Comet for UX design
How to fix iOS 9 problem iPhone stuck screen, unresponsive, no swipe, frozen, can't turn off
Synology invites you to visit them at IP EXPO - Europe’s number one IT event on 7th-8th October. Register HERE for free and join them at stand DD8