IBM 8688 manual Power supply LED errors, Front Power good Good Power on Indicators

Power supply LED errors

Use the power supply LED information on the following page to troubleshoot power supply problems.

Note: The minimum configuration required for the DC Good LED to come on is:

vPower supply

vTop power board

AC	DC	Front	Power good
good	good	power on	indicators
LED	LED	light	(midplane)	Description	FRU/action
Off	Off	Off	Off	No power to system	1.	Check ac power to system.
				or ac problem.
					2.	Power supply.
					3.	Top power board.
On	Off	Off	Off	DC source power	Unplug the three power connectors to the
				problem	midplane board. If the DC Good LED does not
					come on:
					1.	Inspect and replace any damaged power
						cables.
					2.	Check ac power to system.
					3.	Power supply.
					4.	Top power board.
On	On	Blinking	Off	Standby power	1.	Disconnect the following items from the
				problem
						midplane board to isolate the failing FRU:
						a. Light Path cable and SCSI power cable
						b. Memory-board assembly
						c. Processor-board assembly
						d. PCI or PCI-X adapters
						e. PCI-X board
						f. Remote Supervisor Adapter (watch for
							lit or flashing LEDs on I/O board)
						g. I/O board cable attachments
					2.	If LEDs are on after removal, replace the
						offending device.
					3.	If no LEDs are lit after step 1, replace the
						following:
						a.	I/O board
						b.	Midplane board
On	On	On	Off	Failure to power up	1.	Check indicators for a failing VRM; replace
				POWER GOOD
						any failing VRMs.
				problem
					2.	Remove the adapters and disconnect
						cables and power connectors to all internal
						and external devices. Turn on the server.
					3.	If the Power Good LED comes on, replace
						the adapters and devices one at a time
						until you isolate the problem.
					4.	Power supply.
					5.	Top power board.
					6.	Midplane board.
On	On	On	On	Power is OK.	N/A

180IBM xSeries 450 Type 8688: Hardware Maintenance Manual and Troubleshooting Guide