CompTIA A+ Core 1 | Domain 5: Hardware & Network Troubleshooting (28%) | Reading (12 &13)

 

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5.1 Troubleshooting Methodology (MEMORIZE EXACT ORDER)

This is one of the most tested objectives.

 

The 6-Step Process

1. Identify the problem
   2. Establish a theory of probable cause
   3. Test the theory
   4. Establish a plan of action and implement solution
   5. Verify full system functionality
   6. Document findings

 

Key Notes:

• Always start with user questions
• Do NOT skip steps on the exam
• Documentation is always last

 

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 5.2 Safety Procedures

Electrical Safety

• Disconnect power before opening devices
• Use proper grounding

ESD Protection (Electrostatic Discharge)

• Use anti-static wrist strap
• Work on non-conductive surfaces

Environmental Safety

• Avoid liquids near devices
• Ensure proper ventilation

 

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5.3 Common Hardware Problems

No Power

 

Symptoms:

• No lights
• No fan movement

 

Causes:

• Dead PSU
• Loose cables
• Faulty outlet

 

Solutions:

• Check power cable
• Test outlet
• Replace PSU

 

No POST (Power-On Self-Test)

 

Symptoms:

• System powers on but no display
• Beep codes

 

Causes:

• RAM failure
• CPU issue
• Motherboard failure

 

Solutions:

• Reseat RAM
• Test components
• Replace faulty hardware

 

 No Display

 

Causes:

• Monitor off
• Loose cable
• GPU failure

Fix:

• Check connections
• Try different monitor
• Reseat GPU

 

 Beep Codes

• Indicate hardware failure
• Vary by BIOS manufacturer

 

Common Meanings:

• Continuous beeps → RAM issue
• No beep → possible motherboard failure

 

Overheating

 

Causes:

• Dust buildup
• Fan failure
• Poor airflow

 

Fix:

• Clean system
• Replace fan
• Apply thermal paste

 

 Slow Performance

 

Causes:

• Low RAM
• HDD instead of SSD
• Too many background processes

 

Fix:

• Upgrade RAM
• Install SSD
• Close programs

 

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5.4 Storage Troubleshooting

 

Drive Not Detected

 

Causes:

• Loose cable
• BIOS disabled
• Dead drive

 

Fix:

• Check SATA/power
• Enable in BIOS
• Replace drive

 

Slow Disk Performance

 

Causes:

• Fragmentation (HDD)
• Failing drive

 

Fix:

• Defragment (HDD only)
• Replace with SSD

 

Clicking Noise (HDD)

• Mechanical failure
• Immediate backup required

 

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5.5 Network Troubleshooting

No Network Connection

 

Causes:

• Disabled adapter
• Bad cable
• Wrong settings

 

Fix:

• Enable NIC
• Replace cable
• Check IP settings

 

No Internet Access

 

Causes:

• DNS failure
• Gateway issue
• ISP outage

 

Fix:

• Use ipconfig
• Ping gateway
• Check DNS

 

Weak Wi-Fi Signal

 

Causes:

• Distance
• Interference
• Obstacles

 

Fix:

• Move closer
• Change channel
• Use extender

 

Slow Network

Causes:

• Bandwidth congestion
• Old router

 

Fix:

• Switch to 5 GHz
• Upgrade router

 

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5.6 Command-Line Tools (EXAM CRITICAL)

Essential Commands

ipconfig      → View IP settings
ping          → Test connectivity
tracert       → Trace route
nslookup      → DNS lookup
netstat       → Active connections

 

Example Workflow:

1. Run ipconfig → Check IP
2. Run ping 127.0.0.1 → Test local stack
3. Ping gateway → Check local network
4. Ping external → Check internet

 

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 5.7 Wireless Troubleshooting

 

Common Issues:

 

Cannot Connect to Wi-Fi

• Wrong password
• SSID hidden

 

 Interference Sources:

• Microwaves
• Bluetooth devices
• Other networks

 

Fix:

• Restart router
• Change channel
• Forget/reconnect network

 

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5.8 Printer Troubleshooting

 

Common Issues:

 

Paper Jam

• Remove jam carefully

 

No Print Output

• Check ink/toner
• Restart printer

 

Printer Offline

• Check connection
• Restart spooler

 

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5.9 Mobile Device Troubleshooting

 

Issues:

 

Battery Drain

• Background apps
• Old battery

 

 No Connectivity

• Airplane mode
• Network settings

 

Frozen Screen

• Restart device

 

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5.10 Troubleshooting Scenarios (PBQ STYLE)

 

Scenario 1:

PC powers on but no display
Likely: GPU or RAM

 

Scenario 2:

Connected to Wi-Fi but no internet
Likely: DNS or gateway

 

Scenario 3:

Laptop shuts down randomly
Likely: overheating

 

Scenario 4:

Slow PC with HDD
Upgrade to SSD

 

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5.11 Preventive Maintenance

 

Hardware:

• Clean dust regularly
• Check fans

 

Software:

• Update OS
• Scan for malware

 

 Security:

• Use antivirus
• Apply updates

 

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