Need help with a 68K Mac board

Teo Zenios wrote: If there is no disk attached, and there is no termination on a scsi bus (single ended) the bus is held reset. Assuming things: 1. initiator end termination optional: nothing pulls up the bus, so you need to put on a cable with three connectors, middle one connected to the board, and terminators on each of the others. 2. figure out whether the jumpers enable termination on the card, and turn it on. even in this case you may get a bus reset, and have no joy, initiator hangs forever waiting for reset to clear. if there is initiator termination, you still need to attach a terminator to make a properly terminated SE bus. 3. modern card, auto terminates, card firmware should figure out whether one or two terminations are required and apply them. even if you attach a drive, with proper termination, you may still have no initiator end termination if the jumpers are wrong, and have problems booting. Note that everywhere I say initiator termination, I mean termination on the card. This may also take the form of empty component sockets, which take some sort of resistor packages to supply the termination, or even worse some custom thing that was pulled for some reason. SCSI is designed to allow the initator to be in the middle of the device chain, should you need to wire it that way, so someone may have pulled termination on the card. Also, if someone rigged an internal drive (assuming they could wire it) they would have no termination on the card if there were external devices. You would have a bus for example of <internal or disk terminator><internal disk><controller><external disk/tape><external terminator> when the controller was pulled.