IBM DS4700 manual Replace the RAID controllers

Table 51. Symptom-to-FRU index (continued)

Problem
indicator	Component	Possible cause	Possible solutions
One or more	Power supply	Power cable is	Make sure that the power cable
green LEDs are	CRUs	unplugged or	is plugged in and that the
off		switches are turned	switches are turned on.
		off.
	All drive CRUs	Midplane failure	Replace the midplane. Contact
			an IBM technical support
			representative.
	Several CRUs	Hardware failure	Replace the affected CRUs. If
			this does not correct the problem,
			replace the RAID controllers,
			followed by the midplane.
			Contact an IBM technical support
			representative.
	Front panel	Power supply	Make sure that the power cables
		problem	are plugged in and that the
			power supplies are turned on.
		Hardware failure	If any other LEDs are lit, replace
			the midplane. Contact an IBM
			technical support representative.
Intermittent or	Some or all	Defective ac power	Check the ac power source.
sporadic power	CRUs	source or	Reseat all installed power cables
loss to the storage		improperly	and power supplies. If applicable,
subsystem		connected power	check the power components
		cable	(power units or universal power
			supply). Replace defective power
			cables.
		Power supply failure	Check the power supply Fault
			LED on the power supply. If the
			LED is lit, replace the failed CRU.
		Midplane failure	Have the midplane replaced.
			Contact an IBM technical support
			representative.
Unable to access	Drives and	Incorrect storage	Ensure that the fibre-channel
drives	fibre-channel	subsystem ID	optical cables are undamaged
	loop	settings	and properly connected. Check
			the storage subsystem ID
			settings.
			Note: Change the switch
			position only when your storage
			subsystem is powered off.
		RAID controller	Replace one or both RAID
		failure	controllers. Contact an IBM
			technical support representative.
		Drive or drives	Replace failed drive or drives.
		failed
Random errors	Subsystem	Midplane failure	Have the midplane replaced.
			Contact an IBM technical support
			representative.

Chapter 6. Hardware maintenance 187