HP dc7608 manual Solving Power Supply Problems, Problem Cause Solution

				Troubleshooting Without Diagnostics
Solving Power Supply Problems
	Solving Power Supply Problems
	Problem	Cause	Solution
	Power supply shuts down	Voltage selector switch	Select the proper AC voltage.
	intermittently.	on rear of computer
		chassis (some models) is
		not switched to correct
		line voltage.
		Power supply fault.	Replace the power supply.
	Computer powered off	Processor thermal	1.	Ensure that the computer air
	automatically and the	protection activated:		vents are not blocked and the
	Power LED flashes Red two	A fan may be blocked		cooling fan is running.
	times, once every second,	or not turning.	2.	Open hood, press the power
	followed by a two second	OR		button, and see if the processor
	pause, and the computer
		The heatsink/fan		fan spins. If the processor fan is
	beeps two times. Beeps
				not spinning, make sure the
	continue for five iterations	assembly is not properly
				fan's cable is plugged onto the
	after which the LED flashes	attached to the
				system board header. Ensure
	will continue until the	processor.
				the fan is fully/properly seated
	problem is resolved.
				or installed.
			3. If the fan is pugged in and
				seated but not spinning, replace
				the processor fan.
			4.	Reseat processor heatsink and
				verify that the fan assembly is
				properly attached.
	Power LED flashes Red, four	Power failure (power	1.	Check that the voltage selector
	times, once every second,	supply is overloaded).		(some models), is set to the
	followed by a two second			appropriate voltage.
	pause, and the computer		2.	Open the hood and ensure the
	beeps four times. Beeps
				4- or 6-wire power supply cable
	continue for five iterations
				is seated into the connector on
	after which the LED flashes
				the system board.
	will continue until the
			3. Check if a device is causing the
	problem is resolved.
				problem by removing ALL
				attached devices. Power on the
				system. If the system enters the
				POST, then power off and
				replace one device at a time
				and repeat this procedure until
				failure occurs. Replace the
				device causing the failure.
				Continue adding devices one at
				a time to ensure all devices are
				functioning properly.
			4.	Replace the power supply.
			5. Replace the system board.

Service Reference Guide, dc7600 390742-002 D–5