How do I replace Macintosh internal HD and terminate the SCSI chain properly?
The factory installed Macintosh internal HD should be terminated. Make sure the terminator/resitor-package is installed in the drive before using it. Most vendors will install the terminator for you if you tell them it is for use in Macintosh as the system disk. Manufacturers usually have toll free numbers for SCSI termination, ID, and such. If you don’t already have the terminator, they may send you one for free. BTW, Macintosh SCSI chain starts at the system disk (ID=0), and ends at the control board (ID=7). ID numbers from 1-6 should be used for any other devices on the chain.