The system hangs at the blank gray screen, or it hangs at the “Welcome to Mac” Blue OS screen with the ATTO host adapter installed.

* Try booting without the drives attached to the card. If this works:
* Check drives to make sure they are all set to different SCSI ID’s. By default, the host adapter uses SCSI ID 7, so drives should use ID’s 0 through 6, or 8 through 15.
* Check cable integrity. Check the cables for solid connections. Make sure they are screwed down. Inspect cable ends for bent pins.
* Verify the ATTO host adapter has its termination set properly. Instructions to do this can be found in the installation manual.
* If used, verify the external terminator is the correct type (single ended or active – active preferred) and does not have damaged pins.
Most Ultra SCSI hard drives have either a jumper or terminating resistors on the surface of the drive itself (Ultra2 and Ultra3 drives do not). Excess termination frequently occurs when these jumpers or resistors are not removed. This becomes more apparent as more drives are installed in the chain. The user should locate the proper jumper or resistor by contacting the manufacturer of the drive. Make sure termination is “off” on all drives, except the last one in the chain. The last drive should either be terminated by jumper internally or by an external terminator, not both.
* In the case where both internal and external drives are attached to the host adapter, both the last internal and the last external drive need to be terminated.
* If termination is correct, and the problem persists, try drives one at a time with different cables, adding drives and cables until the problem occurs. This will help pinpoint the drive or cable causing the problem.
* If the system still hangs at the blank gray screen without drives attached, try refreshing PRAM. PRAM can become corrupted when changing the hardware configuration of a Macintosh. Hold down the “Command-Option-P-R” keys while starting up the system. Continue to hold down the keys until startup chime is heard three or four times.
* Check for PCI conflicts by removing other PCI cards, if any, and restarting. Also try installing the ATTO host adapter in a different PCI slot.
* If the system still hangs at the blank gray screen without the drives attached, try booting while holding down “Command-Shift-D”. This will disable the Express PCI card from its bus without physically having to remove it. Reflash your card with current firmware.

Knowledge Base