Anyway you need to check why have not communication between computer and image processing pcb. These boards are connected directly. When have 6901-0080 error can be bad ARCNET connection on PCI/ARCNET conversion pcb, bad ARCNET connection on image processing boards, missing power supply on image processing pcb doesn't work ( no response ) .
Check power suppliers on image processing section boards ( image processing, image correction, digital ice ) . Try connect ARCNET cables from image processing to different connectors ( on PCI/ARCNET conversion pcb ) , cut off ends of cables ( 90 degree, use special cutter ) .
If all that will not help need reconnect ARCNET cables on image processing pcb. If will not work - try remove image correction and digital ICE pcb. If still will not work need check image processing pcb, or RAM ( if old model ) .