Laptop Not Charging? Causes and How Technicians Find the Fault

A laptop that will not charge usually has one of four causes: the adapter or cable, the DC jack, the battery, or, less often, the charging circuit on the motherboard. Work through them in that order: each check is quicker and cheaper than the next.

Checks anyone can do first

• Try a different wall socket or extension, and check the adapter's own light if it has one.

• Look along the adapter cable and at both plugs for kinks, cuts and heat marks, and check that the plug sits snugly in the laptop.

• If the battery is removable, take it out and run the laptop on the adapter alone. If it works, the battery is the problem.

• Note exactly what the laptop does: nothing at all, a flickering charging light, or "plugged in, not charging".

• Check the manufacturer's power settings: some laptops have a battery-care mode that stops charging at a set percentage.

The common causes and what each one looks like

A faulty adapter or cable

The laptop does not respond at all, or the charging light flickers. The adapter may get very hot, or the cable may be frayed. The adapter label states its output voltage: a multimeter reading well below that figure means the adapter is faulty.

A loose or damaged DC jack

Charging works only when the plug is held at an angle, the socket wobbles, or there is a burning smell. The fix is to replace the DC jack, which on many laptops means opening the laptop and soldering.

A worn-out battery

The laptop runs on the adapter but the battery will not hold a charge, or the laptop reports "plugged in, not charging". Replacing the battery fixes it.

A swollen battery

If the case is bulging or the trackpad has lifted, the battery is swelling. Stop charging and using the laptop, do not press on or puncture the battery, and have it replaced by a technician.

The charging circuit on the motherboard

The adapter is good, the jack is good, the battery is good, and it still does not charge or even power on. The fault is in the board's power input and charging circuit: the input protection, the power MOSFETs or the charging IC. This is board-level work.

How a technician tests the charging path

1. Measure the adapter's output with a multimeter and compare it with the voltage on its label.

2. Inspect the DC jack and cable, and wiggle-test the plug while watching for the charging light.

3. Try a known-good adapter, and a known-good battery if one is available.

4. Check whether the laptop powers on with the adapter alone and the battery removed.

5. If it does not, check whether power reaches the board at the DC input, then follow the circuit with the schematic and boardview and test the MOSFETs and the charging IC.

Do not probe a powered board unless you know what you are doing: a slipped probe can turn one faulty part into several.

When to stop and get help

• The battery is swollen

• There has been liquid damage

• You smell burning, or the adapter is too hot to hold

• The adapter checks out and the jack and battery are good: the board needs testing

Where technicians learn this

Charging faults are among the first things a laptop technician learns to diagnose. IMT Computers' Laptop Technician Repair course covers laptop chargers and power adapters in week 2 and battery, charging and DC jack replacement in week 7. The charging circuit itself, with the charging IC and power MOSFETs, is taught in weeks 3 and 4 of the Laptop Engineering & Board-Level Repair course. To see how the two courses differ, read what is chip-level laptop repair?

Frequently Asked Questions

Why does my laptop say "plugged in, not charging"?

Usually the battery is worn out, or a power setting is limiting charging. Try the laptop without the battery. If it runs on the adapter, replace the battery. If a battery-care setting is on, the laptop is behaving as designed.

Can a faulty charger damage my laptop?

Yes. An adapter that outputs the wrong voltage can damage a laptop, and so can a poor-quality replacement. Use an adapter that matches the voltage and rating printed on your laptop's label.

Can I replace a DC jack myself?

On many laptops the jack is soldered to the motherboard, so replacing it needs the laptop opened and soldering skills. If you are not trained, a technician should do it.

Want to learn to diagnose and repair laptops yourself? See the Laptop Technician Repair course or compare all four repair courses on Laptop & Phone Repair Training.