G raid 3 2000GB not powering up. What's happening?

Our G-Tech has stopped! When powered up it sounds like it is starting up - the white light comes on…but after a few seconds it all powers down. Been reading up a bit here and elsewhere to see hat I can do to A - get it going or B relieve data to new backup.

It’s been connected to a very new iMac but the GTech is several years old. Never a prob, although we have just plugged in and used not really set it up in any way … yes next time - learning every day!

It has run with time Machine all along.
Thanks in advance