FC can implement software RAID, but I'm pretty sure that'll be 0 or 1 at the most - I doubt it can do RAID5. You'll need a dedicated hardware controller for that.
Is it a Dell Poweredge server you're dealing with? If you've replaced the redundant PSU and the blue light is still blinking, press the "i" button on the server a couple of time. Hopefully you'll then get a constant blue light indicating everything is OK.
If not, and you're sure the PSU's are OK, then maybe something else is wrong. Run Dell diagnostics if you're unable to work out what it might be.
From an OS point of view you could always take a look at the output of dmesg or /var/log/messages