Hi,
Well incase anyone ever stumbles upon this thread I thought I should post the outcome.
I managed to track down a logic board from SafeOnComputer, from eBay. He actually sent me two, one with almost identical codes, but with an Agere controller chip and one slightly different but with an ST chip. The ST chip one had a similar but different p/n, (I will try and edit this post with the details if I can find the bit of paper I scribbled it on before sending them back.)
Anyway, the Agere one span up but didnt detect in BIOS, the ST one (after resoldering on a tiny component that came off in transit!) detected and seemed to be ok.
To cut a long story short, I eventually used Raid Reconstructor to sector image each drive with this new logic board on, then mounted them in Captain Nemo as a single recontrcuted drive. I got the entire data set back (160Gb) bar 3 files. These all >1Gb files but were 0 bytes - so at least they were obviouusly not right rather than corrupted. Amongst everything I had 10Gb of RAR files to check that passed CRC test. All other things I could find appeared fine as best as I could test. I was almost 100% sure integrity had remained therefore.
Initially after trying the new board on a drive, I had tried replacing the old board, but it was still dead. This seemed quite normal.
Now the interesting part. After I had imaged both drives, I accidently connected the first one back up with its original dead logic board on. To my amazement it was working. I then put the old board back on the second too and that worked?! Now both drives were alive again. It appeared this only happened after they had both been hooked up with the replacement board for a few hours while sector copying (as I had tried changing to old pcb at the begiining after swapout and was still dead)
Anyone can explain this???
Anyway I bought a PCI Sil3112 raid card to try them on with the old pcb's. This was because my old nforce board used a Sil controller, and my new one was ICH9R intel. (Incidently raid recontructor uses drive on any channel so you can get data from drives from different raid controller, without needing any raid controller). They did pick up on it as a valid raid set, unfortunately they didnt work so windows could see them as a drive - it appeared the partition was damaged somehow. I spent quite a while trying to fix it but could not.
Just for completeness in the post - other things I did - I imaged the two sector copies back to a pair of 120gb drives, these also picked up on the raid controller but with bad partition. (probably not surprising as different size) - i used GetDataback for NTFS but didnt get much from them.
I would like to say a big thank you to SafgeOnComputer and
www.runtime.org (& rameez who offered me a PCB but due to delay had allready got one on order from SafeonComputer -although that did cost me $59.99)