All Red Drives on Drobo FS

So, whilst trying to find the serial number of my Drobo FS - its on the bottom of the casing - my power cable came loose, when I plugged it back in ALL of my drives were indicated flashing red… Have I lost all my data? Have I lost the drives? have I lost the Drobo?
The array included a 3 week installed brand new 3TB WD NAS drive and 4 other 2 and 3 TB drives…

All lights red would be “Too many drives removed”, I’d suggest you power off, carefully re-seat all the drives, wait a little while & power back on. By all means clean the unit out while you have the drives out to ensure no dust or debris is trapped in the connectors if you can do so.

I have done exactly as suggested and also cleaned the terminals with Isopropanol - all lights are still red.

In that case, things got a bit more complex.

What happens when you boot with no drives?
What happens if you boot with a spare drive (one which hasn’t been in a Drobo)?
Is your “new” drive on this list of incompatible ones? Can I really use any hard drive I want in Drobo? Note that WD (and others) changed the technology used in some drives recently without changing model names only numbers.

No way I’d have moved/disturbed a Drobo while it was powered on & running, we’re getting into difficult territory with no guarantees now.