SCSI adapter is not seen during POST / bootup - Servers and IntelliStation

Resolving The Problem

When a SCSI adapter is not seen during POST/bootup, it is usually because of one of the following reasons:

1. The adapter is not seated well

• Reseat the adapter and remove all cables to the adapter. All that is desired at this point is to see if the adapter is seen on boot. Most SCSI adapters will give the "Press Ctrl+A" message when the system is going through boot, however this message may have been disabled.
  • By removing the adapter from the machine, it is also without power. Without power, most SCSI adapters fall back to default settings.
  • If it still doesn't show up, test it in another PCI slot or in another system; make sure no cables are attached.
  • Test another SCSI adapter in the PCI slot that this one was in.
• Most IBM servers use Active PCI or Hot-Plug PCI. These PCI slots are powered slots, and if the retention latch is not closed completely, then there will be no power to the adapter thus causing the adapter not to show up in POST.
  • Make sure to lower the tab over the top corner of the adapter. Rotate the adapter retention latch clockwise until it snaps into place.
  • If it becomes apparent that the adapter is not the problem and the PCI slot is the problem, run system board diagnostics and contact IBM support. (See below).
• If the new SCSI adapter does show up, and even moving the other adapter to another machine doesn't work, the adapter may require a BIOS update or it may be damaged.
  • Contact IBM support and advise the steps done in problem determination to continue troubleshooting. (See link below).
• If the adapter does show up after moving it to another system, go into the Control+A for the adapter. Most SCSI adapters that IBM supports are Adaptec-based. There are 2 options: SCSI device configuration, and SCSI device Utilities.
  • Choose the option SCSI device configuration and reset the card to factory defaults again. This is normally F6, however read the menu items to make sure.
  • Try the adapter in the system again.

2. An IRQ conflict between another adapter

• If there are several adapters in the system, it could be that an IRQ conflict is occurring.
  • It may be required to remove the additional adapters.
  • Always check IBM ServerProven for compatibility information on options used in the server.
• To correct the conflict, boot up the system into its F1 BIOS setup configuration utility.
  • Select Advanced configuration options and look for PCI Bus Controls or PCI Controls.
  • Under this menu there should be a menu selection to allow change of PCI IRQs, such as PCI Interrupt Control.
  • By default PCI interrupts are normally set to autoconfigure. By highlighting them and pressing Enter, it is possible to change these settings.
  • Be aware that in some IBM systems the settings for PCI interrupts are in hexadecimal.
• See the User's Guide for exact information on setting IRQs and configuring BIOS settings.

3. If the SCSI controller is imbedded into the system board, make sure it is enabled

• Imbedded SCSI controllers have one of 2 methods of enabling them.
  • On some IBM systems, there is a jumper on the system board to disable / enable the embedded SCSI Controller.
  • On most newer IBM systems, the control setting for this is a setting within F1 BIOS setup.
    • That setting is normally under the Devices and I/Os Menu in most IBM systems.
• If the controller has been disabled, it obviously will not be visible. However, another clue that the controller is disabled is if, during POST, the following message is received: "Onboard device has been disabled by the user."
• See the User's Guide for exact information on jumper settings and configuring BIOS settings.

4. SCSI termination must be set correctly

• Termination is always done at the adapter, and at the end of the SCSI chain. The only exception to this is if both internal and external 16-bit devices are being used off of the same adapter. This causes the adapter to do pass-thru SCSI and termination is required at both ends of the SCSI chain.
  • SCSI adapters have a termination setting within the SCSI Select Utility. The default setting for termination is Automatic. It is suggested to leave this setting.
• Determine if the SCSI cable in use is self-terminating. To do this, visually inspect the end of the cable for a black block.
  • If the black block is present, this is a terminated cable. Now confirm that none of the devices attached to this cable are set to provide termination. Termination cannot be set more than once.
  • If the black block is not present, this is not a terminated cable. Now confirm that termination is provided by a device on the SCSI bus. There must only be one device set to terminate, and the terminating device must be connected at the end of the SCSI chain.
• If the SCSI cable is not self terminating, verify if it is 8 bit or 16 bit and terminate the SCSI chain either using a active terminator or on the last device in the chain.
  • 16 bit or wide cabling should be terminated with a 16 bit or wide terminator or device. If a 8 bit terminator is used on a 16 bit cable, only the lower bits will be terminated. This causes the higher bits to bounce along the SCSI cable and can cause SCSI communication problems.

  Note: Inspect each SCSI device for the following problems; ID, damaged connector, power connected, cable, termination

5. SCSI ID must be set correctly for all devices on the SCSI chain

• By default the SCSI adapter is normally set to ID 7. It is suggested to leave the setting at its default, and if during troubleshooting you find that the ID has been changed, Load Default Settings of the SCSI adapter, which will reset the adapter's ID back to 7.
  • An UltraSCSI adapter supports SCSI IDs 0 to 15.
• If you install additional SCSI devices, you must set a unique ID for each SCSI device that you connect to the SCSI cable.
  • The SCSI device ID is also known as the SCSI address or physical unit number (PUN).
  • This unique ID enables the SCSI adapter to identify the devices and to prevent two devices from sending or receiving data on the SCSI bus at the same time.
• SCSI devices use a variety of methods to set the SCSI ID, such as jumpers, thumbwheels, or switches.
• The default startup (boot) SCSI ID is 0 for a SCSI hard disk drive.
• Use the SCSI Device Utility in the SCSI-Select program to view the SCSI IDs of SCSI devices in the system. (See Using the SCSI Select Utility program for more information.)
• If you install wide (16-bit) SCSI devices, you can set the IDs to any number between 0 and 6, or between 8 and 15. If you install narrow (8-bit) SCSI devices, you can set the IDs to any number between 0 and 6.

If the tip above does not solve the issue, or an IBM component is determined to be faulty, please contact your local IBM Support Center for further troubleshooting or warranty replacement of parts. Please have your Machine Type-Model, serial number, and component Field Replacement Unit (FRU) / Customer Replacement Unit (CRU) part numbers available.

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