Laptop Hardware: Replacing Batteries, Keyboards, RAM, Storage, Wireless Cards, Cameras, and Biometrics
Unit 1: Mobile Devices. Lesson 1 of 41 in APlus Academy Core 1.
A laptop packs desktop parts into a case that was never designed to be opened every week. Core 1 expects you to know which parts a technician replaces, how to reach them without breaking anything, and the details that catch people the first time.
Before you open anything
- Back up the user's data if the drive is involved in any way.
- Shut down fully (not sleep or hibernate), unplug the power adapter, and remove the battery or disconnect the internal battery connector from the board.
- Hold the power button for about ten seconds to drain any remaining charge.
- Put on an ESD strap and work on an ESD mat. Lay screws out in a labeled map; laptops mix several screw lengths, and a long screw in a short hole cracks the board or the palm rest.
- Photograph the cable routing before you lift a single connector.
Battery
Modern laptops use a lithium-ion pack. Most are internal, held by a few screws and a connector under the bottom cover; older machines have a latch-release pack on the underside. A battery that will not hold a charge, reports poor health, or has swollen gets replaced, never opened or punctured. Swelling shows up as a trackpad or keyboard pushed upward. Stop using the machine and replace the pack.
Keyboard and keys
A single keycap snaps onto a scissor mechanism and can be replaced alone. The whole keyboard connects to the board by a flat ribbon cable in a ZIF (zero insertion force) connector: flip the latch, slide the cable out, reverse to install. A liquid spill usually kills the keyboard first and the board second.
Memory
Laptop RAM is a SODIMM, seated in an angled slot under a cover or under the keyboard. Push the side clips outward, the module tilts up, pull it out. Match the generation exactly (DDR4 into DDR4) and check the maximum the board supports. Many thin laptops solder the memory to the board; then the upgrade is a new laptop.
Storage
Either a 2.5-inch SATA drive in a caddy or an M.2 card. M.2 comes in SATA and NVMe versions with different keys and lengths (2280 is the most common), so check the slot before ordering. Clone the old drive first if the operating system must survive the swap.
Wireless card
A small M.2 2230 card with two tiny antenna leads snapped onto it. The antenna wires run through the hinge into the lid and around the display, where they get the best signal. The leads are marked main and aux (often one black, one white or gray); put each on its labeled terminal. A lead left off gives weak or no signal.
Camera, microphone, and biometrics
The webcam and microphone sit in the lid bezel with a cable through the hinge, sometimes behind a physical privacy shutter. Fingerprint readers live in the power button or the palm rest; smart card readers are in the side; NFC badge readers (the near-field scanner feature) hide under the palm rest. Each is a module with a connector: replace the module, then reinstall its driver.
Laptop Hardware: Replacing Batteries, Keyboards, RAM, Storage, Wireless Cards, Cameras, and Biometrics, explained slowly
Why laptops are a separate skill
A desktop is a box with room to move. A laptop is a sandwich: the bottom cover, the board, the battery, the keyboard, and the display are stacked and screwed together, with ribbon cables threaded between them. Every replacement means undoing part of the stack in the right order and putting it back without pinching a cable or stripping a screw. The exam tests the order and the gotchas, not brand-specific steps.
The sandwich, layer by layer
lid display panel, webcam and microphone, wireless antennas around the panel hinge display cable, camera cable, and the two antenna leads pass through here top cover keyboard (ribbon to the board), trackpad, fingerprint reader, NFC reader board CPU (soldered), RAM (SODIMM slots or soldered), M.2 storage, M.2 wireless card battery flat lithium-ion pack under the palm rest, connector to the board bottom cover with screws of several lengths; vents; sometimes an access door
Most modern service starts by removing the bottom cover, which exposes the battery connector, RAM, storage, and wireless card. Keyboards and trackpads usually need the board or the top cover out.
A worked replacement: the wireless card
A user's laptop shows one bar of Wi-Fi at their desk while a phone next to it shows full signal. The card is suspect.
- Shut down, unplug, remove the bottom cover, disconnect the battery.
- The card is an M.2 2230 module held by one screw, with two hair-thin coaxial leads clipped to it. Note which lead is on which terminal (main and aux; usually one black, one white or gray) before touching them.
- Remove the screw; the card tilts up; slide it out. Seat the new card, screw it down, press each antenna lead straight down onto its terminal until it clicks.
- Reconnect the battery, replace the cover, boot, and install the driver.
If the signal is still one bar, the fault is an antenna lead broken where it passes through the hinge, and the fix is a new antenna assembly in the lid. That is the exam's favorite detail: the antennas are in the lid, around the display, because the base is full of metal and sits low.
A worked replacement: RAM
A laptop with 4 GB is sluggish with a browser open. The board has two SODIMM slots, one empty.
- Check the maximum the board supports and the generation in the slot (DDR4 will not fit a DDR5 slot; the notch differs).
- Insert the new module at about a 30-degree angle until the contacts disappear, then press down until the side clips snap.
- Boot and confirm the total in firmware or the OS. If only the old amount shows, reseat; a module not pressed fully home is the usual cause.
If there is no slot at all, the memory is soldered and the honest answer is "this laptop cannot be upgraded."
Batteries deserve respect
symptom action holds 30 minutes, health under 60% replace the pack laptop only runs on the adapter replace the pack (or the charging circuit if a new pack does not help) trackpad or keyboard bulging up swollen cell: stop use, do not press, replace, recycle properly
Never puncture or bend a swollen pack, never toss one in the trash, and never leave a removed pack shorted in a bag of screws.
How the exam asks it
- "Before replacing a laptop keyboard, what should the technician do FIRST?" Disconnect the AC adapter and the battery.
- "A user replaced a laptop's wireless card and now has weak signal. Most likely cause?" An antenna lead is not connected.
- "Where are a laptop's wireless antennas located?" In the lid, around the display.
- "Which memory module type fits a laptop?" SODIMM.
- "The trackpad on a laptop has started to bulge. What should be done?" Replace the battery; it is swollen.
What to memorize
- Power off, unplug, disconnect the battery, ESD strap, screw map, photos.
- SODIMM at an angle, then press down; match the generation; soldered means not upgradable.
- M.2 for storage (check key and length) and for wireless (2230 with two antenna leads).
- Antennas in the lid, through the hinge. Camera and microphone in the lid bezel.
- Fingerprint in the power button or palm rest; smart card in the side; NFC under the palm rest.