One night my 2nd gen Drobo had 4 green lights, all healthy, with sufficient space. The next morning my started flickering all lights red in a bad way. I had seen this before, and replacing the power brick fixed it, so I bought another similar power brick on eBay.
This time, upon plugging in the new power adapter and booting the drobo, it keeps all 4 bay lights on solid red for 15 seconds, then all four lights off for 15 seconds, and repeat. Also the blue capacity lights flash on for a second or so before switching from solid red to off.
Power cycling the drobo has no effect. 4 drives are resident in the bays.
I guess the drobo has lived a long life and I should have been prepared to retire it. I just wish there were better diagnostics here. Is the problem still the power brick? Or some other hardware failure? Anyone seen this before, or want to offer last ditch troubleshooting ideas?