A+ Exam Objective 5.2 – ExamNotes
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5.2 Given a scenario, troubleshoot problems related to motherboards,
RAM, CPUs, and power.
Welcome to ExamNotes by CertBlaster! Moving right along, we’re at the fifth out of five Main Domains! We are also almost finished with the Hardware side of
the CompTIA A+ objectives. In this section, we will mainly focus on troubleshooting with regards to the devices themselves as well as any issues involving
network connectivity. You really need to have a solid grasp of each of these objectives in order to have a chance of beating the test. Here they are!
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Common symptoms
When you have a system crashing unexpectedly, it’s good to have a list of things to check. This list should consist of items known to cause general problems such
as overheating, memory problems, and power problems. The important thing is to determine what area of the system is likely causing the issue and to
systematically test every possible cause of that issue. This can take seconds or days to diagnose depending on your methods.
For example, if you know you are having a video problem that appears to be memory related, what type of memory should you check first? Say the machine is
using RAM Boost. Would you check that first? Probably not.
What about the main system memory? L2? L3? Video memory?
In this example, the smart money would be on the video memory as the culprit. Check the video memory using the video diagnostics tool from the manufacturer
of the graphics card. If the computer has upgradeable memory, try removing it. The graphics will be slower, but your problem may disappear.
Use your knowledge of how the system components interact with each other and compare that with what you see and hear.
Let’s look at the system problems in the order presented in the objectives. The first problem listed happens to be one of the toughest to diagnose.
Unexpected shutdowns
This condition can be caused by anything from a bad power supply to system memory, the processor, or even the motherboard. So if the cause can be basically
anything, where do you start? First, allow the system to cool down to room temperature, shut it off, and move onto something else until the system components
and heat sinks are cool to the touch.
Now start the machine. If it’s your machine, follow your normal usage pattern until the crash presents itself again. What were you doing when the crash
occurred? Do the contributing elements appear to be related to system load, a specific program, or is it simply a matter of operating time? If it’s a user machine,
observe the user’s actions and ask questions.
System lockups
Lockups will be diagnosed much the same way as unexpected shutdowns, however this time with an emphasis on heat related conditions.
System error in Event Viewer
Here is a typical error shown in the event viewer. After recovery, always try to use the Event Viewer to find out what caused the problem.
POST code beeps
When there is a speaker present on the motherboard, audible codes will sound which provide high value system failure information, giving the technician good
detail on the system level failures prior to successful POST. This series of long and short beeps will direct the technician to the component or subsystem that has
failed or is not otherwise present. This is quality information that is delivered before the screen data is visible.
Unfortunately, these audible codes are always different from one UFEI/BIOS manufacturer to the next.
Proprietary crash screens (BSOD/pin wheel)
This condition is more often referred to as a “hang” than a crash. During this condition, a single program or a group of processes will stop responding to
operator input. When diagnosing this condition, always give the program in use a few seconds to respond. Sometimes it is that simple. If this doesn’t work, use
the task manager to examine the running processes and see which process is “Not Responding.” Examine the tasks and processes involved since it’s often more
than one. Once identified, end the offending tasks.
Blank screen on bootup
This condition has several accompanying conditions, a couple of which are shown below.
System boots to BSOD – Blue Screen of Death
BSOD – Blue Screen of Death
Troubleshoot by looking up the STOP: error code displayed on the BSOD and follow the instructions if relevant. These codes tend to be generic. Sometimes,
there may be several related to the same incident, as you can see in the image. You may have to gather clues from each instance.
Black error screen on boot
Sometimes you will receive a black screen with a short “Humane” message such as “PCI Wireless card not connecting. Check the connections.” Albeit rare, these
messages do exist. These messages will show when there is enough information presented to the bootloader for it to provide specifically actionable feedback to
the user. The best examples of this are “Boot to Safe Mode” and “Boot to Last Known Good Configuration.”
BIOS time and settings resets
Many Startup errors can be attributed to power settings. One classic example of this is when your system date and time reverts back to something irrational.
At this point in your studies, you will have covered the BIOS settings on a PC and how the BIOS settings are stored, modified, and maintained.
CMOS Battery
When the device is off, the information stored in the BIOS is saved using a small watch battery, more specifically a 2032 type battery. This is a very power efficient
method of storing essential system configuration information.
Attempts to boot to incorrect device
Among the system settings stored on the UEFI/BIOS are the Drive or Hard Disk information. This includes the Hard Drive boot order. The Drive or Hard Disk
information tells the read/write heads where to look for the boot information as well as the preferred boot drive selection.
Continuous reboots
Sometimes, a continuous series of reboots will be caused by a failed update or software corruption. More often than not however, the continuous reboot
situation is usually caused by a failing motherboard component, the processor, or RAM.
No power
A no power condition is diagnosable by the general lack of noise, fan operation, drive operation, and lights. Check all of your power sources, wall outlet, and
power strip. If these are okay, check the connections to the motherboard.
Overheating
This is a serious condition with potentially severe consequences. The circuitry used in today’s components can only tolerate so many extremes of hot or cold. The
greatest danger for circuitry is heat. Fortunately, there are sensors built into the motherboard that can detect temperature extremes and either issue a warning
or shut down the system.
Causes of overheating can be due to clogged airways where the internal air circulation is impeded or where there is excessive dust buildup on heat exchanging
surfaces such as the aluminum fins, heat pipes, and fan/cooler assemblies. When you hear an odd sound coming from the case, it is probably the heat sensor. The
sound will be loud and distinct enough to not to be mistaken for anything else.
Intermittent device failure
An intermittent failure can have a number of causes such as a failing processor, motherboard, RAM, or bad drivers. Check the processor temperature first and
then run RAM diagnostics.
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Fans spin – no power to other devices
If the fans spin, you know that 12V power is being delivered to the system since fans and drive motors operate on the 12 Volt power channel. Some of the logic
boards and indicator lights use 5 Volts or 3.3 Volts.
Smoke/ Burning smell
Anytime you smell electrical components burning or smell or see smoke, cut the power to the device(s). This is serious. Get the device outdoors since burning
components can create noxious fumes.
Distended capacitors
Capacitors store energy until they are released. When looking at the top of the capacitor, you can see the pressure relief scores. These cross-shaped indentations
serve to create a weak area that will allow the capacitor to vent as opposed to exploding. You can see that two of the capacitors have already failed in the image
below.
Failing capacitors
Tools
Multimeter
A Multimeter is a tool capable of measuring a wide range of both positive and negative electrical values. A Multimeter is used to measure two or more electrical
values, usually two of the following three: voltage (Volts), current (Amps), and resistance (Ohms). A Multimeter is an essential tool for any technician. As you
spend time in the field, you will realize that the majority of the problems you will see have their root in electrical power. Invest wisely in your meter.
You can get a good analog meter and it will serve you well. Consider that these are fragile instruments and require you to pre-set the value range you expect to
see. If you don’t set the correct value range, you run the risk of damaging the indicator pin.
There is an easier and more accurate alternative to the analog meter. This is a digital Multimeter. You will find that most digital Multimeters are auto ranging,
eliminating the potential for damage. In addition, the readings you get on a digital Multimeter are quite clearly defined as opposed to an analog Multimeter
where an accurate reading depends on the angle you are viewing the meter from.
Two types of multimeters
Power supply tester
A Power supply tester functions much in the same way as a Multimeter, except it looks for specific ranges. When using a good power supply tester, the first thing
you will notice is that the values are constantly fluctuating. This is because most power sources vary within a tolerable percentage throughout the day due to the
load or number of electrical devices being used and the quality of the incoming power. Please do not call the power utility if you encounter this. These variances
are all kept within tolerance and mainly concern your line voltage, which will be between 100 to 125 Volts AC. You will see smaller incremental variations in the
measurements of your device. The device will accept variations and will not warn or alarm you unless the values are dangerously low or high.
Most people think high voltage is the only thing you have to worry about, but low voltage can also be problematic for electronics. A good tester will monitor DC
Positive voltages of 12 Volts, 5 Volts, and 3.3 Volts. As you can see in the digital output of the tester shown in the image below, all the readings are close but only
one is “spot on.” Given these variances, the meter rates each range as good. There will be connections on the device which accept different power connectors
such as ATX P1, Molex, and SATA.
Power supply tester
Loopback plugs
Loopback plugs are essentially devices that send signals to themselves. Self-contained, these devices are able to diagnose the sending and receiving of data on
the interface being tested.
Loopback plug
POST Card/ USB
Next, we come to the POST Card/USB. The POST card has been around for a long time and has been instrumental in diagnosing many hardware failures that
occur before POST completes. USB now makes it possible to perform POST level diagnostics without opening the case. For (typically) under $10, you can
diagnose all the functions performed during POST and you can use the digital code sent to see where your problem is.
Log entries and error messages
Always use all the tools available to diagnose and troubleshoot RAM, CPU, and power problems. If you can access the operating system, you will be able to use
diagnostic tools such as Resource Monitor in order to examine the resource usage and look for issues that could appear to be related to hardware. You can also
use the Performance Monitor to view and log selected performance data over time in order to evaluate any changes you make.
Finally, we’ll talk about Event Viewer again. Here you will be able to view system events and filter them to suit your requirements. Even BSODs will be tracked
here.
That’s all for objective 5.2! Good luck on the test!