Been there. I bought an Oktagon 2008 and NEC 210 for my A4000 many years ago. The NEC drive does not meet the SCSI protocol (not even SCSI 1) and will work to some extent if it is the only thing on the SCSI bus. But I think the whole bus hangs if there is anything else on it.
Throw out the NEC drive. Newer drives are cheap as dirt these days. Also make sure you update the ROM on the 2008 board (I can't remember how, but it was a Flash update).
tony