Drobo 5N & 5N2 single red light of death

I see that plenty of people have woken up to a Drobo 5N/5N2 dead with a single red light.
Anyone figure out how to fix it?
Resetting, re-seating drives, replacing the PSU, all fail.

Does anyone know what on the motherboard may be at fault? Drobo support have been responsive however they won’t provide me the details of what the cause of this is - I’ve asked for schematics etc so that I could do the fix myself however they have said no in each case.

They have offered for me to sip the unit to them and offer to repair it for $350 (assuming the could).

I have three other Drobo FS that are 10 years old now and they work perfectly. I’ve never heard of an FS having this ‘single red light of death’. It must be specific to the design of the 5N/5N2 and an inherit fault.

It’s a pity they won’t be more forthcoming given that they are trying to restructure. They’re only losing customers with their behaviour as I see it.