Resolving a loose cable connection
If a connection is loose from the device to the cable, or from the cable to the device, problems with a device might occur.
Check the connections and verify that the cable connections are correct and secure.
For SCSI devices, check that the SCSI terminators are correct and that there are no bent pins in the terminator itself. An improperly terminated SCSI bus might result in difficult problems with one or more devices on that bus.