Hi. Have you checked the POWER SUPPLY? Get a volt meter and see if it is putting out 12V DC. It sounds like there isn't enough current or voltage to run the drives.
You could try another power supply so long as it has the same voltage rating 12VDC and the same or higher AMP rating. I think that device has a 2 Amp (2000mA) output. So for example, 3000mA would be ok, but 1000mA would NOT be ok. It must be 12 or 13 VDC. anything else would probably not work. You can probably find a cheap one around and splice the connector on from the old power supply. IF it is confirmed not working, you have nothing to loose.
I personally ran mine off solar power, so direct, regulated 12 VDC and my motherboard has died. That could be possible with yours. Mine was about the same age at the time of death. I think those machines are mostly JUNK. A mini-itx based solution would be much better and easier to recover in the case of emergency. I ended up loosing my data because the motherboard came back on and it started REFORMATTING with RAID1. I came back to find both my drives blank. Even data recovery was near impossible because Linux erases the partition table at the beginning and end of the partition at the same time!!!!
Here's a tip for anyone doing RAID - Linux is about THE WORST thing to use for RAID because the way the filesystem is written (as mentioned above). Windows, as bad as it is in MUCH better in regards to recovery because it doesn't touch the end MBR until everything has been completed. It's because of that I can easily say that Linux filesystems have a LONG way to go in order to be accepted in the enterprise world. If you're running this for your company, think twice. It's not a SAFE device. Even if the DATA is ok, what happens when the hardware fails? Can you easily, quickly, and cheaply replace it? I DOUBT it. THat means downtime. A better solution is needed and WD's support both HARDWARE and SOFTWARE is terrible. YES we can hack this thing, but should we HAVE to? Without the hacks this thing is a TURD at best. A REAL solution would be to do RAID5 or RAID6. That is the ONLY way I could recommend using a Linux filesystem for IMPORTANT data. Otherwise you're playing Russian Roulette with your data. I'm not exaggerating here.
Sorry to sound negative, but I'm being honest and realistic. I know the negative sides of this device well as I've experienced the worst, and could NEVER look someone else in the eye and recommend such a product. EVER. It's a fun toy at most. Nothing more. You've been warned. I hope this is helpful to someone like me that didn't realize the risks when I started using this device.