IT FundamentalsA+

Laptop Troubleshooting for CompTIA A+ 220-1101

Laptop troubleshooting requires addressing hardware issues unique to the portable form factor — battery, display, keyboard, touchpad, and thermal management. CompTIA A+ 220-1101 tests common laptop hardware problems, their causes, and solutions. Many laptop repairs involve disassembly — understanding risks and limitations is as important as knowing the fix.

7 min

2 sections · 7 exam key points

1 practice questions

Display and Input Troubleshooting

Display issues: no image — verify brightness (Fn + brightness key), ensure laptop is not in sleep/hibernate (press power button briefly or tap trackpad). External display only works: internal display cable may be loose or display backlight inverter failed (CCFL — older laptops) or panel failed. Connect external monitor to test — if external works, internal display is the issue. Dim display: backlight failure or brightness set to minimum. Flickering: loose display cable (hinge area — cables wear as lid opens/closes thousands of times).

Keyboard issues: specific keys not working — debris under key (use compressed air), key cap broken (replacement keycap or full keyboard replacement). Some keys work but others don't: spill damage (clean with IPA carefully if dried, or replace keyboard). Full keyboard not working: keyboard ribbon cable dislodged from connector — open service panel and reseat. NumLock on (makes number keys map to numpad) — press Fn + NumLock. Function keys not working: check Fn Lock key status.

Touchpad issues: not responding — check if touchpad is enabled (Fn + touchpad toggle key). Driver issue — Device Manager → update or roll back touchpad driver. Physical damage. An external mouse was connected and somehow disabled the touchpad (check settings — some laptops disable touchpad when external mouse connected). Dirty touchpad surface — clean with dry cloth.

Battery, Power, and Thermal Issues

Battery not charging: check AC adapter connection (both ends). Try a different outlet. Verify correct adapter wattage (100W charging port requires 100W adapter — lower wattage adapter may trickle charge or not charge at all). In Windows: Battery icon → plug in to charge should indicate charging. Check BIOS for battery threshold settings (some manufacturers allow setting max charge to 80% for battery longevity). Degraded battery: charge rapidly but drain quickly — replace battery.

Not turning on: verify AC adapter is providing power (LED indicator on adapter, test with multimeter if needed). Try power-only without battery — if it starts, battery is preventing startup (disconnect battery, boot on AC). Drained battery: some laptops won't start until battery has minimum charge — plug in for 15 minutes before trying. Hard reset: disconnect AC, remove battery, hold power button for 30 seconds (drains residual capacitor charge), reinsert battery, plug in, try power.

Overheating and thermal shutdown: laptop shuts down under load or runs hot. Clean vents with compressed air (hold fans still while blowing — spinning fan by air can damage bearings). Check that laptop is used on hard flat surfaces (not pillows/blankets that block vents). Reapply thermal paste on older laptops. Laptop cooling pad: external USB-powered fan stand provides additional airflow.

Slow performance: check Task Manager for high CPU/RAM usage. Check thermal throttling — if CPU is throttling due to heat, cleaning the heatsink may restore performance. Check for malware (background processes). Insufficient RAM or slow storage for the workload.

Key exam facts — A+

External monitor works but internal doesn't: display cable, backlight, or panel failure
Display flickering: often hinge-area cable wear from repeated lid opening/closing
Keyboard ribbon cable: reseat if full keyboard fails — common after disassembly
Battery not charging: check adapter wattage, connection, battery threshold settings
Hard reset: remove battery + AC, hold power 30s, reinsert — drains residual charge
Thermal shutdown: clean vents (hold fan still), reapply thermal paste, use hard surface
NumLock causing key issues: Fn + NumLock to toggle

Common exam traps

Using a laptop on a bed or pillow doesn't affect performance

Soft surfaces block the bottom vents of laptops, severely restricting airflow and causing temperatures to spike within minutes. This leads to thermal throttling (reduced performance) and shortened component life. Always use laptops on hard, flat surfaces. If you must use on a soft surface, a laptop cooling stand or tray provides airflow clearance

Practice questions — Laptop Troubleshooting

These questions are representative of what you will see on A+ exams. The correct answer and explanation are shown immediately below each question.

Q1.A user reports their laptop keyboard has stopped working after they spilled a small amount of water on it yesterday. External USB keyboard works fine. What is the most cost-effective repair?

A.Replace the entire motherboard

B.Replace the laptop keyboard assembly

C.Buy a new laptop

D.Update keyboard drivers

Explanation: Spill damage typically affects only the keyboard — water intrusion corrodes key contacts. Since an external USB keyboard works, the keyboard controller on the motherboard is functional. The fix is to replace the internal keyboard assembly — a relatively affordable laptop-specific part (typically $10–$50 depending on the model). Motherboard replacement is expensive and unnecessary since the keyboard controller works. Driver updates don't fix physical corrosion damage.

Frequently asked questions — Laptop Troubleshooting

What should you do immediately if a laptop has a liquid spill?

Act within seconds: 1) Power off immediately — press and hold the power button. 2) Disconnect AC adapter. 3) Remove the battery if accessible (removable battery). 4) Flip the laptop upside down to allow liquid to drain away from components. 5) Do NOT use a hairdryer — heat damages components and can push liquid further in. 6) Allow to dry for 24–48 hours minimum (72 hours for significant spills). 7) After drying, reinsert battery and attempt to power on. Clean with 90%+ isopropyl alcohol if sticky residue remains. Many spills are recoverable if power is cut immediately.

Practice this topic

A+practice questions

Test yourself on Laptop Troubleshooting

JT Exams routes you to questions in your exact weak areas — automatically, after every session.

Free practice test Start 7-Day Free Trial

No credit card · Cancel anytime