The answer is a faulty battery management system (BMS). When a laptop battery stops charging but the AC adapter is confirmed to output correct voltage, the BMS is the most likely failed component because it governs the charging logic and communication between the battery cells and the laptop. Even if the individual lithium-ion cells are healthy, a failed BMS will prevent the battery from accepting a charge or reporting its status, leaving the system to run only on AC power. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of battery charging circuitry and the BMS’s role as the “gatekeeper” for power flow. A common trap is to assume the cells themselves are dead, but the BMS failure is the root cause when the adapter is verified working. Remember the memory tip: “BMS blocks the charge” — if the adapter is good but the battery won’t charge, suspect the management system, not the cells.
220-1101 Mobile Device Hardware Servicing Practice Question
This 220-1201 practice question tests your understanding of mobile device hardware servicing. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user reports that their laptop battery no longer charges and the system only runs when plugged in. You test the AC adapter and it outputs correct voltage. Inside the battery, which component is most likely failed?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The battery management system (BMS) is faulty.
This question covers battery charging circuitry. The battery management system (BMS) controls charging and communicates with the laptop. If the BMS fails, the battery may not accept a charge even if cells are good. The AC adapter is verified working, so the issue is inside the battery.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The lithium-ion cells have degraded.
Why it's wrong here
Degraded cells would still show some charge or cause shorter runtime, not a complete failure to charge.
✓
The battery management system (BMS) is faulty.
Why this is correct
A failed BMS prevents the battery from communicating with the charger and accepting power, causing no charging.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The DC jack on the laptop is loose.
Why it's wrong here
The DC jack issue would affect power to the whole system, but the system runs fine on AC adapter.
✗
The laptop's motherboard charging circuit is damaged.
Why it's wrong here
If the motherboard circuit were bad, the system wouldn't run on AC power either.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
Degraded cells would still show some charge or cause shorter runtime, not a complete failure to charge.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Mobile Device Hardware Servicing — This question tests Mobile Device Hardware Servicing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The battery management system (BMS) is faulty. — This question covers battery charging circuitry. The battery management system (BMS) controls charging and communicates with the laptop. If the BMS fails, the battery may not accept a charge even if cells are good. The AC adapter is verified working, so the issue is inside the battery.
What should I do if I get this 220-1201 question wrong?
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A customer complains that their laptop battery no longer holds a charge and the laptop only works when plugged in. The technician confirms the battery is removable. What is the most appropriate first step in servicing this issue?
easy
A.Update the battery driver in Device Manager.
B.Run a battery calibration utility from the manufacturer.
✓ C.Power off the laptop and remove the battery.
D.Replace the AC adapter to see if the charging circuit is faulty.
Why C: The correct first step is to power off the laptop and remove the battery. This ensures safety and prevents electrical shorts or damage during replacement. After removal, the technician can install a new battery.
Last reviewed: Jun 18, 2026
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