Yamaha AW4416 manual About terminators, About SCSI errors, Check the SCSI ID, Check the terminator

Before you begin

❒About terminators

“Termination” refers to the process of applying a resistor appropriate for the impedance of the SCSI bus to terminate the end of the circuit. The resistor required for this is called the “terminator.” Normally, a terminator must be installed at the beginning and end of the SCSI bus (in the case of the example shown above, this would be the AW4416 itself, and the SCSI device connected to the end of the daisy chain).

However, this is only a general principle, and is not an absolute. Depending on the combination of SCSI devices, the order of connection, or on the length of the SCSI cables, there may be cases in which better results are obtained by terminat- ing only one end of the chain. If problems occur such as the AW4416 failing to start up when an external SCSI device is connected, try defeating one of the ter- minators. (For details on how to defeat the internal terminator of the AW4416, refer to “UTILITY screen → Prefer. 3 page” in the Reference Guide.)

❒About SCSI errors

The SCSI bus is able to transfer data in a stable manner only if all connected SCSI devices are operating correctly. If the SCSI bus of the AW4416 is connected to a device whose operation is unstable or which produces noise, errors may occur in other devices, or the AW4416 may fail to start up correctly. If such problems occur, check the following points.

❍Check the SCSI ID

Make sure that the SCSI ID of each SCSI device (including the AW4416 and the internal CD-RW drive) does not conflict with the SCSI ID of any other device. The SCSI ID of the AW4416 is fixed at “6.”

❍Check the terminator

Check the location of the terminator. Under certain conditions, better results may be obtained by terminating only one end of the SCSI chain.

❍Check the SCSI cables

Since errors are often caused by low-quality SCSI cables or unnecessarily long SCSI cables, you should avoid using such cables. Please use double-shielded cables that are as short as possible. It is also important that the shield within the cable is grounded to the connector.

❍External SCSI devices with 25-pin connectors

Most SCSI cables with 25-pin connectors at both ends do not meet SCSI specifi- cations. For this reason if the system includes a SCSI device that uses a 25-pin connector, the problems may be due to this type of cable.

12 — Operation Guide