We repair PCs, Windows laptops and Android because we do the hardest job in the trade

What it usually is. On almost every recent Android the glass, the touch layer and the panel are bonded into a single block, so replacing just the glass isn’t a thing: the whole assembly goes. Whether the image works and touch doesn’t, or the other way round, doesn’t change the part, but it does tell you the phone underneath is still alive and that the data can be pulled off before anything is opened.

What not to do in the meantime. Don’t keep using it with splintered glass or stick a protector over the crack to get by: pressing on it drives the shards inwards, cutting the touch layer and the seal. If you can also see a dark patch spreading or coloured lines, stop using it, because that grows every day and takes the working part of the screen with it. And back up your photos today, while there is still a screen to do it from.

What it usually is. The simple explanations go first: lint packed into the bottom of the port and a cable that has broken inside. When it’s neither, the port is worn or the board has stopped managing charging. On some models that port sits on a small daughterboard and on others it’s soldered to the main one, and that difference decides whether the job is a module swap or soldering under a microscope.

What not to do in the meantime. Don’t scrape inside the port with a needle, a paperclip or a toothpick: the contacts are hair-thin and once bent no cable will grip them again. And don’t leave it charging overnight in the position that works, with the cable propped up by a book: a bad contact heats the port, and the battery sits right next to it.

What it usually is. A phone that shrugged off a splash the day it left the factory tells you nothing about the state of its seals now: gaskets dry out, and any previous opening — a screen, a battery — leaves them worse than they were. And water doesn’t break things outright, it corrodes: the damage keeps advancing for days, which is why a phone that seemed to have survived fails a fortnight later.

What not to do in the meantime. Not rice: it dries nothing inside and pushes starch and dust into the connectors. Don’t switch it on to check, and above all don’t put it on charge, because damp with current running through it corrodes far faster. No hairdryer and no radiator either, since heat drives the water further in. Turn it off, don’t shake it, and bring it in quickly.

What it usually is. Two very different situations hide behind the same picture. One is software — an update that stopped halfway, a damaged partition — and the other is the board: power that never comes up, memory that doesn’t answer, a chip that heats and cuts out. The first move is to put it on a lab supply and watch how much current it draws: a phone pulling nothing and a phone pulling too much aren’t the same problem.

What not to do in the meantime. Don’t run a factory reset or wipe anything from recovery mode to break the loop: if the fault is on the board you’re no better off, and the photos are gone as well. On Android the storage is soldered and encrypted against that particular phone, so whatever is erased there isn’t coming back. And don’t leave it on a fast charger for hours hoping it reacts.

What it usually is. A laptop that doesn’t stir when you press the button with the charger plugged in almost never has a Windows problem: it has a power problem. Inside the board the supply rails come up in a chain, and one rail failing to rise leaves everything dead with nothing visible to point at. A shorted charging controller, a cracked capacitor or a track eaten away by damp all look exactly like this, and they are told apart by measuring current draw on the bench. This is the ground where repairing a board component by component changes the ending, because the usual answer to it’s a new board or nothing.

What not to do in the meantime. Don’t repeat the unplug-and-hold-the-button trick twenty times over: if there’s a short, every attempt heats the same component again and one point to repair becomes three. Don’t try the charger from another laptop just because the plug fits, since neither the voltage nor the negotiation is the same on every machine. And if it got wet or took a fall before this started, say so when you bring it in: it changes where the search begins.

What it usually is. That message doesn’t say the battery is dead: it says the system has decided not to charge it. It can be the battery, the gauge reporting its state, or the charging circuit on the board, and it’s the fault most often “solved” by buying a battery that was never the problem. It gets clearer once you check whether the charger is delivering the voltage it should and whether current is actually going in.

What not to do in the meantime. Don’t order a battery online before you know the battery is the problem: if the charging circuit is what failed, the new one won’t charge either. Don’t reach for a universal charger with swappable tips to get by. And don’t settle into working plugged in for months, because a battery that drops to zero and stays there really does degrade, and that’s the one that swells later.

What it usually is. On most laptops today the charging port — the old round barrel or a USB-C — is soldered straight to the board. When somebody trips over the cable, the yank doesn’t stop at the connector: it tears off the pads and tracks underneath. Putting it back is therefore not a part swap but soldering under a microscope and rebuilding what came away.

What not to do in the meantime. Don’t charge it holding the cable by hand or wedging it with a book at the angle that works: an intermittent contact throws tiny sparks at the joint itself, and that heat burns tracks until there is nothing sound left to solder to. If the port runs unusually hot, smells, or has gone loose in its housing, unplug it and leave it alone until someone looks at it.

What it usually is. Cutting out dead only under load points at two places: temperature or power delivery. Either the machine hits its thermal limit and shuts down to protect itself, or the stage feeding the processor and the graphics can no longer hold the current peak they ask for and the rail sags for an instant. On laptops with dedicated graphics the two usually travel together. Logging temperatures and draw while it’s being pushed separates them without opening anything.

What not to do in the meantime. Don’t use it on a bed, a sofa or your lap: the vents end up covered and the machine breathes its own hot air. Don’t leave it running flat out to see whether it holds, because every hard cut is a risk to the file system and one day the thing that won’t start is Windows itself. And don’t take the bottom cover off or leave it loose so it can breathe: without it the air comes in where it should not and the heatsink stops pulling heat away.

What it usually is. Almost always the cooling underneath is choked: the thermal paste has dried out and the heatsink sits behind a felt of dust and hair that no air gets through. When the processor can’t shed heat it throttles itself to avoid cooking, and that’s what you feel as slowness. Less often the heat is the effect rather than the cause: a drive on its last legs, or something working away in the background that nobody asked for.

What not to do in the meantime. Don’t stand it on fabric or cover it while it’s working. Don’t blast it with canned air while the fan is spinning: forced round like that the fan behaves as a generator, and that spike can take out the electronics driving it, while the dust ends up further in rather than out. And don’t call it fixed by pinning the fans at maximum with an app: that mutes the warning, it doesn’t clear the heatsink.

What it usually is. If the machine starts up — fan, drive light, backlit keyboard — the fault lies in the chain that carries the picture to the panel, not in the power-up. It can be the backlight, the display cable that runs through the hinge, the panel itself, or the video output on the board. One test costs nothing and says a great deal: plug in an external monitor. If the external screen shows a picture, the computer is healthy and the problem lives from the hinge upwards.

What not to do in the meantime. Don’t keep opening and closing the lid to see whether it comes back: if the cable running through the hinge is what has broken, every open severs one more strand and an intermittent picture becomes no picture at all. And don’t tap the bezel or press on it to make contact, which is how a panel that still worked ends up cracked.

What it usually is. The hinge is screwed into plastic anchors inside the lid. Once it seizes, all the force of opening the laptop lands on those anchors: they snap, and as they snap they push the case apart from inside. That’s why you first see a corner lifting, then a gaping seam, and finally a pinched display cable or a cracked panel. Fixing it properly isn’t tightening the screw, it’s rebuilding the anchor so there is something to hold on to again.

What not to do in the meantime. Don’t carry on opening and closing it carefully in the hope it holds: every open pulls a little harder on what’s already broken, and the next stage costs far more. Don’t force it shut or carry it in a bag half closed. And don’t reach for superglue: cyanoacrylate leaves the plastic brittle, and then there is no sound material left to anchor the repair to.

What it usually is. If individual keys fail, the keyboard itself is the suspect: dried drink underneath, a punctured membrane, worn contacts. If the whole thing dies at once, or goes down together with the trackpad, look further in: both hang off latched ribbon connectors on the board, which work loose with a knock or after years of heat, and behind them sits the controller that drives them. A USB keyboard settles a lot: if everything works over USB, the computer is fine and it’s the internal input that has failed.

What not to do in the meantime. Don’t tug the ribbon cable or push it back in without releasing the connector latch: they are foils a fraction of a millimetre thick and they crack the moment they are bent, and then it isn’t the keyboard any more, it’s the board. Don’t lever the keycaps off with a knife to clean underneath, because the clips don’t go back. And if it died right after a drink went over it, don’t switch it on: that’s a spill, not a keyboard.

What it usually is. On a laptop the keyboard is the lid: whatever you spill goes down between the keys and lands straight on the board, which sits right underneath. Water is the least bad of them; sugared coffee, beer, fizzy drinks and soup leave salts and sugars that keep eating the tracks for weeks, with the machine switched off and put away. The job is to open it quickly, disconnect the battery, clean the board thoroughly and rebuild whatever the corrosion has already taken.

What not to do in the meantime. Don’t switch it on to see whether it still works, which is exactly what burns the board. Hold the power button until it shuts down completely, take the charger off and leave it open and face down on a towel. No hairdryer, no radiator, no oven: heat drives the liquid further in, and caramelised sugar on the chips is worse still. And don’t wait a few days for it to dry, because what moves in those days is the corrosion.

What it usually is. A drive that stops mounting can have a logical fault — a partition table wrecked by a power cut, a file system broken mid-write — or a physical one: the SSD electronics, worn-out cells, the mechanics of a spinning disk. A PC works in your favour here, because the storage almost always sits on a separate module and can be taken out and worked on away from the broken machine instead of waiting for it to boot. And the urgent thing isn’t getting the system back, it’s what’s inside.

What not to do in the meantime. Don’t accept the automatic repair the system offers at startup and don’t run a disk check to see whether it sorts itself out: both write to the volume and, if there’s a physical fault underneath, they write right over what could still have been recovered. If it offers to format, say no. Don’t install recovery software onto the same drive you’re trying to recover. And if it’s a spinning disk and it clicks, unplug it and leave it unplugged.