I recently had a CX II go bad and the only replacement was on in a box that said it didn't see the hard drive. Threw it on the bench with a drive that had failed in a raid system that I hadn't had time to test. Upon boot up, the march test hung, might have got a failed message but knew memory was bad. Put in a stick from a customer who I upgraded to the 1GB and found this controller to function. Customer was restored and we looked good.
Yes your problem is memory, I have also gotten new controllers with memory failure in the past