Try this:
- Disconnect the drives
- Boot up
- Open Apple System Profiler
- Does the iMac show a Firewire bus as "being there"? (even with nothing attached to it). It should indicate that there is Firewire "present" (again, with nothing attached).
- Quit System Profiler
Next:
- Connect ONE of the drives
- Do you hear the drive mechanism "spin up" inside the enclosure?
- Relaunch System Profiler.
- Check the Firewire info again.
- It should now indicate the "presence" of the external device. Has anything changed?
If NOTHING HAS CHANGED, looks like the internal firewire bus isn't recognizing the drive (assuming the drive has spun up).
I'm guessing you tried both of the following procedures already, "by the numbers", is that correct?
1. Shut down the computer.
2. Disconnect all devices and all other cables, except the keyboard and mouse cable(s).
3. Disconnect the computer from the power outlet and wait for 3 to 5 minutes.
4. Plug the computer back in and turn it on.
5. Reconnect the device(s) (one at a time if there is more than one) and test. Test with each port if you have more than one."
source:
http://support.apple.com/kb/HT1317
Try resetting something called nvram:
"Resetting PRAM and NVRAM
1. Shut down the computer.
2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys."
source:
http://support.apple.com/kb/ht1379
If you get this far and nothing has worked, I think the next thing to do would be to try connecting the drives to ANOTHER Mac and see if they mount there.
If they do, your firewire port may be either temporarily or permanently broken/disabled (I've heard of cases where after a while, they mysteriously "reactivate" themselves).
If you come to that conclusion, don't despair. You can still "get at" your data if the drive mechanisms themselves are good (they probably are).
Going further....
If the drives can be mounted on another Mac - but not on YOUR iMac - the solution is to buy one or more external drives and "copy the files over" and then go to another connection method on your iMac (I'd suggest USB).
For copying them over, I'd suggest one of these:
http://www.amazon.com/Syba-Connecla...?ie=UTF8&s=electronics&qid=1253062702&sr=1-22
Get one or two 1tb SATA "bare drives" to use with it (my recommendation is for Seagate drives).
Then take everything to the "working Mac" and use CarbonCopyCloner (free) to "do the dupes".
You can now use the SATA dock and your bare drives on the iMac.
There's another way, BUT IT INVOLVES OPENING THE WESTERN DIGITAL DRIVES THAT YOU NOW HAVE (but aren't working in their enclosures).
I'm going to _guess_ that the two "MyBook" drives use SATA drives inside their enclosures.
If this is the case, you could just break the seals on the enclosures, take out the drives, and use them directly with the SATA docking station in the link above. Of course, this will void whatever warranty is left on them. But bear in mind that if you sent the drives back to WD for a warranty replacement, they MIGHT send you back "empty" drives - that is to say, any data on those drives would be gone.
It's a Hobson's choice: either break the seals, pull the drives out, void the warranty, and save your data - OR - send the drives back and risk losing your data. Your choice.
Conclusions:
FIRST OPTION:
Do the two procedures above to attempt to "re-activate" the misbehaving firewire port (if, indeed, it is "misbehaving")
SECOND OPTION:
Take the two firewire drives to another Mac and try them there, to see if they work/don't work properly on a different Mac. If they "mount up", it's a BIG relief!
THIRD OPTION:
Buy a USB connection solution and a couple more drives, and use another Mac to "copy your data over". Then try connecting to YOUR iMac via USB.
FOURTH OPTION:
Buy a USB connection solution, break open the WD enclosures, and try your bare drives with a USB connection method.
Good luck!