Table 9-2 Motherboard, RAM, CPU, and Power Symptoms, Causes, Solutions

Symptom	Possible	Items to Check	Typical Solution
	Cause
Unexpected	Bad power sup-	Check the Power	Replace the power supply
shutdowns	ply	Good and other volt-	if bad.
		age on power supply
		with multimeter.
System lock-	Overheating	Check the fans on the	Replace defective fans.
ups		CPU and in the case	Clean up dirty components.
		for proper operation.
		Check the case, RAM,
		and motherboard for
		dirt and dust.
	Memory error	Check the memory for	Test memory modules with
		proper installation.	Windows Memory Diagnostic
			or third-party utilities; replace
			defective RAM.
POST code	RAM, video,	Look up the beep code	Replace the defective item.
beeps	motherboard,	in the BIOS documen-
	others	tation.
Blank screen	Monitor turned	Verify that the moni-	Replace the monitor if
upon boot	off or discon-	tor is turned on and	defective.
	nected	connected to a work-
		ing video port.

Monitor con-nected to dis-abled video port

Verify the monitor is turned on and con-nected to a working video port.

Enable a video port or con-nect a monitor to another video port on the system.

Monitor config- Use the monitor’s

ured to look for onscreen menu to select

incorrect video the correct video port

signal (DVI or VGA, HDMI

or VGA, and so on).

Save the new default setting on the monitor.

	40-wire PATA	Verify the correct ori-	Replace a 40-wire cable
	cable connected in	entation of the 40-wire	(not always keyed) with a
	reverse prevents	PATA cable connected	80-wire cable.
	video display	to the hard disk.
	None of the	Use a POST card	Look up the last code
	above	(Figure 9-3) to deter-	displayed in the BIOS
		mine how far the boot	documentation to diagnose
		process goes before	problems.
		stopping.

166 CompTIA A+ Quick Reference

Table 9-2 Continued

Symptom	Possible	Items to Check	Typical Solution
	Cause
BIOS time and	CMOS battery	Check the battery with	If the battery fails, or if it
settings resets	failure	a battery tester.	is more than 2 years old,
			replace it with a fresh bat-
			tery. (Most motherboards
			use CR-2032.)
Attempts to	Incorrect boot	Start the BIOS setup	Restart the computer.
boot to incor-	order in CMOS	program, verify that	If the boot continues to fail,
rect device	setup	the boot sequence lists
check CMOS settings. If
		hard disk, and remove
		settings not retained, replace
		media that might have
		the CMOS battery and redo
		bootable files.
		settings.
Continuous	Incorrect voltage	Check the Power	If Power Good voltage is out
reboots	on Power Good	Good voltage with a	of range, replace the power
	line from power	multimeter.	supply.
	supply

No power Power supply Verify the power sup-

unplugged ply plugged into a

working AC outlet.

If the system will not start, continue.

Power supply	Verify that the power	If the power supply was set
set for incorrect	supply has the correct	for 230V on a 115V circuit,
voltage	voltage level selected.	no harm done.
		If the system will not start
		after setting correct voltage,
		continue.
		If the power supply was set
		for 115V on a 230V circuit,
		check to see if the power
		supply and other compo-
		nents have been damaged or
		destroyed.
Power switch	Check the front-panel	If cables are connected prop-
from case not	wiring from the case	erly, or system does not start
properly con-	to the front-panel con-	after reconnecting cables,
nected to moth-	nectors on the moth-	test power supply.
erboard	erboard (see Figure
	9-4).

Chapter 9: Troubleshooting 167