Session 2: Laptops, Safety & Identification

Most computer repair is low-voltage and safe, but three things are not. Mains power — never work on a machine that is plugged in, and do not rely on the power switch being off; unplug it. A desktop power supply contains capacitors that hold a charge after unplugging and can deliver a genuine shock, so never open a power supply unit unless you know what you are doing; the professional habit is to replace a suspect supply rather than repair it, because a new one costs less than an injury.

The third is the lithium battery in a laptop. These store a great deal of energy, and if punctured, bent or shorted they can heat rapidly, swell and in the worst case catch fire. The rules are firm: never use a metal tool to lever a battery out, never continue working on a battery that is swollen — a swollen pack is a hazard and must be removed carefully and disposed of properly, not put back in a drawer — and if a battery is heavily glued in place, use a recommended solvent and patience rather than force.

Beyond injury, there is the risk to the machine. Shorting a connector with a screwdriver while a battery is connected can kill a board instantly. The habit that prevents almost all of it: unplug the mains, then disconnect the internal battery, before touching anything else. On a laptop that means the battery connector comes out first, before any other work begins.

Electrostatic discharge is a small spark you usually cannot feel, and it can damage semiconductor components in a way that does not fail immediately. A board damaged by static may work for weeks and then fail intermittently — which is the worst possible outcome, because the failure appears unrelated to your work and the customer concludes you broke it.

The protection is simple and cheap. An anti-static wrist strap clipped to a grounded point keeps you at the same potential as the machine. If you do not have one, touch an unpainted metal part of the case before handling components, and keep doing so. Work on a hard surface rather than carpet, which generates charge; do not work in a nylon shirt on a dry day if you can avoid it. Keep components in their anti-static bags until the moment you fit them, and handle boards by their edges rather than touching contacts or chips.

Be honest about the risk level: modern components are more resistant than they were, and a great many repairs happen without a strap and nothing goes wrong. But the cost of the precaution is trivial and the cost of intermittent failure is your reputation, so the strap is worth wearing on every job — and it is also a visible signal of professionalism that customers notice.

A repair workspace needs four things. Good light — a lamp directed into the machine, because a dropped screw or a missed connector is invisible in poor light. Organisation — a magnetic mat or a set of small containers, because laptop screws are of several different lengths and driving a long screw into a short hole can crack a board. Space to lay a machine open and keep parts in order. And a clean surface, because dust is the enemy you will be removing.

The tool kit that covers most work: a precision screwdriver set with Phillips PH00, PH0 and PH1 bits plus Torx T5 and T6, which covers nearly every laptop and desktop; a plastic spudger and a set of plastic pry tools for clips and adhesive, because a metal tool marks a case and can cut a cable; tweezers for small connectors; isopropyl alcohol at 90% or higher and lint-free cloths for cleaning; compressed air for dust; and a multimeter for power and continuity work from session five onward. Add thermal paste, a CMOS battery and a known-good RAM stick and SSD as diagnostic spares.

The organisation habit matters more than the tools. Photograph before you disassemble, and lay screws out in the order you removed them — a magnetic mat with a drawn outline of the machine is the cheapest way to guarantee that every screw goes back into its own hole. Most catastrophic repair outcomes are not diagnostic failures; they are a long screw forced into a short hole.

'It is an HP laptop' is not enough to order a part. You need the exact model number, and there are three ways to get it. On the machine itself: a label on the base, under the battery on older laptops, or in the battery compartment. In the firmware: press the manufacturer's key during startup — commonly F1, F2, F10, Del or Esc — to enter BIOS, where the model and serial are displayed. Or in Windows: System Information (`msinfo32`) shows the system model, and `wmic csproduct get name, version, identifyingnumber` in a terminal prints them directly.

Distinguish the model number from the serial number and from the marketing name. 'HP Pavilion 15' is a marketing name covering many different machines with different boards, screens and keyboards. 'HP 15-cs3021nr' is a model. The serial identifies that individual unit for warranty purposes. Parts are ordered against the model, and sometimes against a specific part number printed on the component itself — which is why, for screens, keyboards and batteries, the reliable method is to open the machine and read the number off the part.

This is the single most common source of wasted money in repair work: ordering a part against a marketing name and receiving something that does not fit. Take the time to get the model number, photograph the label, and where possible read the part number off the failed component before ordering.

Before opening an unfamiliar machine, find its service manual or a teardown video. Manufacturers such as Dell, HP and Lenovo publish service manuals listing the disassembly sequence, screw lengths, part numbers and what is removable. Where no manual exists, a teardown video for that exact model shows the sequence and the traps — which screws are hidden under rubber feet or under the keyboard, which clips are fragile, where the display cable runs.

This ten minutes of research prevents almost every bad outcome in disassembly. A technician who opens a machine cold will snap a clip, strip a screw or tear a cable; one who has watched a teardown will know that the keyboard must come off first, that three screws hide under the rubber strip, and that the battery connector is under a plastic cover. The difference in outcome is not skill — it is preparation.

For sourcing parts, the reliable order is: the manufacturer's spare parts store using the part number; then a reputable specialist supplier; then a general marketplace, where you must read reviews and check the part number matches exactly. In Nigeria, computer villages and established online vendors carry common parts, but always confirm the model and, for screens, the exact part number and connector type — a screen that fits physically but has a different connector or resolution is a common and expensive mistake.