This could be:
Smart Array controller / cache module has failed.
Drive Cage failure.
Dual HDD failure.
Cable failure.
Have you made any changes?
Check if every thing is firmly seated.
Check if Smart Array controller is detected during POST.
During POST, you get the bullits in the lower right corner turn blue.
Check for the Smart Array bullit.
When all bullits has turned blue, you get a prompt saying "Hit any key to ........"
If you hit Any key, you will see the ILo discovery and F8 prompt
And if the Smart Array Controller is still functional, it will be discovered and you will get a F8 prompt as well.
If you do see the Smart Array controller and get the F8 prompt, check if it can see the disks.
Also Check the IML, for HW failures. You can do that using the ILo or the Insight Diagnostics (HW test tool).
To run Insight Diagnostics.
Download the Latest SPP and the USB usility from hp.com/go/hpsc.
BR
/jag
So far you have replaced the drives and the RAID controller.
Could be Drive cage
Cables
Power to the drive cage
Cache module?
Firmware upgrade is a good idea, but I don't belive it will fix your failure.
Hmmm. Long shot. Could also be a system I/O bd failure - PCI slot/bus - I have seen that once. I can't remember what the failure looked like, but when Smart Array controller was installed on the PCI slots on the sys i/O bd. it failed. When I installed the SA in the PCI Riser cage, it worked.
You really need access to parts for this one.
BR
/jag