IBM DCS9550 1S1 - Manual (Page 53)

Troubleshooting and Problem Solving
38 IBM System Storage DCS9550 1S1 Storage Expansion Unit Installation, Service, and User Guide
4.2.2 Alarm Sounds On Power Up
Please refer to Section 4.4 .
4.2.3 Green “Signal Good” LED on SCM Not Lit
Check that the cables have not been reversed during installation.
4.2.4 Computer Doesn’t Recognize the DCS9550 1S1 Storage Expansion Unit
1 Check that the FC-AL interface cables from the DCS9550 1S1 Storage Expansion Unit to the
host computer, or RAID controller, are fitted correctly.
2 Check the Enclosure ID switch settings on your DCS9550 1S1 Storage Expansion Unit and on
your system host.
3 Check that the LEDs on all installed drive carrier modules are illuminated Green. Note that the
drive LEDs will not be lit during drive spinup.
4 Check that all drive carrier modules have been correctly installed.
5 Check that there is a valid FC_AL signal present at the I/O connector (see section 2.4.1 .) If
there is no signal present check that the cable has not been reversed during installation.
6 Check the SCM I/O module setup as follows:
– Check that the SCM I/O module has been correctly installed and all external links and cables are
securely fitted.
– Check that the maximum cable length has not been exceeded.
4.3 LEDs
Green LEDs are always used for good or positive indication, flashing Green/Amber if non-
critical conditions exist. Amber LEDs indicate there is a critical fault present within the
module.
4.3.1 Power Supply/Cooling Module
The Power Supply Cooling LEDs are shown in Table 4–1 .
• Under Normal conditions the LEDs should all be illuminated constant GREEN
• If a problem is detected the color of the relevant LED will change to AMBER.