Solving power supply problems

This section presents power supply troubleshooting scenarios.

Testing power supply

Before replacing the power supply, use the Built-In Self-Test (BIST) feature to learn if the power supply still works.

To test the power supply:

1.Unplug the AC power.

2.Remove the internal power supply cables from system board (you do not need to remove power supply from chassis).

3.Plug in AC power and verify the following:

●If the green BIST LED on the rear of the workstation is illuminated and the fan is spinning, the power supply is functional.

●If the green BIST LED is not illuminated or the fan is not spinning, replace the power supply.

See the Rear panel components section of this service guide to locate the BIST LED on this workstation.

Problem	Cause	Solution

Power supply shuts down	Power supply fault.	Replace the power supply.
intermittently.

Workstation powers off and the	Processor thermal protection	1.	Ensure that the workstation air vents are not blocked.
Power LED flashes red 2 times	is activated.	2.	Open the access panel and press the workstation
(once every second), followed by a		2.	Open the access panel and press the workstation
(once every second), followed by a	A fan might be blocked or not		power button.
2-second pause.	turning.
	turning.	3.	Verify that the system fan is running.
	OR	3.	Verify that the system fan is running.
	OR	4.	Verify that the processor heatsink fan spins.
	The processor heatsink fan	4.	Verify that the processor heatsink fan spins.
	The processor heatsink fan		If the heatsink fan is not spinning, verify that the fan
	assembly is not properly		If the heatsink fan is not spinning, verify that the fan
	assembly is not properly		cable is plugged into the system board connector.
	attached to the processor.		cable is plugged into the system board connector.
	attached to the processor.		Verify that the fan is properly seated.
			Verify that the fan is properly seated.
		5.	Replace the processor heatsink.

Power LED flashes red (once every 2 seconds).

Power failure (power supply is 1.	Determine whether a device is causing the problem
overloaded).	by performing the following:
	a.	Disconnect AC power.
	b.	Remove all attached devices.
	c.	Power on the workstation.
	If the system enters the POST, perform the following:
	a.	Power off the workstation.
	b.	Replace one device at a time and repeat this
		procedure until a failure occurs.

ENWW	Troubleshooting scenarios and solutions 119