HP 1105 manual Replace one device at a time

Activity	Beeps	Possible Cause	Recommended Action
Red Power LED flashes two	2	Thermal protection	1.	Clean the air vents on the front, back, or
times, once every second,		activated:		any other vented side of the computer.
followed by a two second		Air flow is restricted, a fan	2.	Ensure that there is a 10.2 cm (4 in)
pause. Beeps stop after fifth
iteration but LEDs continue		may not be functioning, or		clearance on all vented sides of the
until problem is solved.		the heatsink is not		computer to permit the required airflow.
		properly attached.	3.	Ensure that computers are not so near
				each other that they are subject to each
				other's re-circulated or preheated air.
			4.	If the computer is within an enclosure,
				ensure that there is proper intake and
				exhaust ventilation for the enclosure.
			5.	If a message appears on the screen
				indicating that a fan is not working, replace
				the fan.
			6.	Ensure that the heat sink is properly
				attached.
Red Power LED flashes three	3	Processor not installed	1.	Check to see that the processor is present.
times, once every second,		(not an indicator of bad	2.	Reseat the processor.
followed by a two second		processor).
pause. Beeps stop after fifth
iteration but LEDs continue
until problem is solved.
Red Power LED flashes four	4	Power failure (power	1.	Open the hood and ensure the 4 or 6-wire
times, once every second,		supply is overloaded).		power supply cable is seated into the
followed by a two second				connector on the system board.
pause. Beeps stop after fifth			2.	Check if a device is causing the problem by
iteration but LEDs continue
until problem is solved.				removing ALL attached devices (such as
				hard, diskette, or optical drives, and
				expansion cards). 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 that is causing the
				failure. Continue adding devices one at a
				time to ensure all devices are functioning
				properly.
			3.	Replace the power supply.
			4.	Replace the system board.
Red Power LED flashes five	5	Pre-video memory error.	CAUTION: To avoid damage to the DIMMs or
times, once every second,			the system board, you must unplug the computer
followed by a two second			power cord before attempting to reseat, install, or
pause. Beeps stop after fifth			remove a DIMM module.
iteration but LEDs continue			1.	Reseat DIMMs.
until problem is solved.
			2.	Replace DIMMs one at a time to isolate the
				faulty module.
			3.	Replace third-party memory with HP
				memory.
			4.	Replace the system board.

134 Appendix D POST Error Messages