Troubleshooting guides
53 guides that start from the symptom rather than the device. Each one explains what is actually happening and links to the test that confirms it.
Any device
- How to test used hardware before you buyA checklist for meeting a seller with fifteen minutes and a phone. Every check here runs in a browser, so you need nothing installed.
- Test your camera and audio before a meetingCheck your webcam, microphone and speakers before a call with a short sequence that separates device problems from meeting-app settings.
- What browser hardware tests can and can’t tell youUnderstand which hardware signals a browser can observe and where device diagnostics, app settings or physical inspection are still needed.
Keyboard Test
Open the keyboard test- How to clean a mechanical keyboardMost intermittent keys are debris, not failed switches. Here is how to clean a board properly, including what not to do.
- Keyboard ghosting and rollover explainedKeys that stop registering when you hold several at once are usually a design limit, not a fault. Here is how to tell which one you have hit.
- Some of my keyboard keys have stopped workingWhether it is one dead key or a whole row, the pattern of which keys failed tells you what broke and whether it is worth fixing.
- My keyboard is repeating keysA key that types itself over and over is either physically stuck or a repeat setting. One is a fault and the other is configuration.
- My keyboard is typing the wrong lettersWrong characters almost never mean broken hardware. Here is how to tell a layout mismatch from a genuine fault in under a minute.
- My laptop keyboard isn’t workingA laptop keyboard that stops working is usually Filter Keys, a driver or a loose internal cable rather than dead keys. Test it to find out which.
Mouse Test
Open the mouse test- How long do mouse switches last?Ratings are given in millions of clicks, but chatter arrives long before the rating does. Here is what the numbers actually predict.
- How to replace the switches in your mouseSwapping a chattering switch costs a couple of dollars in parts. It also requires desoldering, so here is what the job actually involves.
- Why does my mouse let go while I’m dragging?Files drop halfway and text selections stop short. A click that releases while you hold it is usually the same worn switch that causes double clicking.
- Why does my mouse cursor jump or stutter?Erratic cursor movement is a sensor or surface problem, not a button one. Here is how to separate the surface from the hardware.
- Mouse polling rate: does 1000Hz vs 8000Hz matter?Polling rate is how often your mouse reports its position. Here’s what going past 1000Hz actually gains, what it costs and why a browser can’t measure it.
- Why does my scroll wheel jump or scroll the wrong way?A wheel that scrolls up when you scroll down has a dirty or failing encoder. Here is how to tell that apart from a driver problem.
- Optical vs mechanical mouse switchesOptical switches physically can’t develop double click chatter. That one difference decides whether a mouse can fail the most common way mice fail.
- Test mouse side buttons and the scroll-wheel clickCheck mouse side buttons and middle click while separating browser navigation, remapped controls and scroll movement from actual button input.
- Why is my mouse double clicking on a single click?A single click registering as two is almost always a worn switch bouncing. Here is how to confirm it and what actually fixes it.
Dead Pixel Test
Open the dead pixel test- Backlight bleed or IPS glow? How to tellBright corners on a dark screen are either backlight bleed or IPS glow. One is a build defect and one is how the panel works. A head movement tells you which.
- Dead pixel or stuck pixel? How to tellThe two faults look similar and get confused constantly, but only one can be fixed. Telling them apart takes about thirty seconds.
- How many dead pixels are acceptable?Manufacturers allow a surprising number of defective pixels before a panel counts as faulty. Here are the actual ISO thresholds by resolution.
- How to check an OLED screen for burn-inBurn-in shows as a faint ghost of your taskbar or a game HUD on flat colors. Here’s how to find it, how to tell it from image retention and what helps.
- How to claim a warranty for dead pixelsMost single-pixel claims are refused because they sit inside the allowance. Here is how to document a claim and when a return beats a warranty.
- How to fix a stuck pixelA stuck pixel can sometimes be revived. A dead one can’t. Here is how to tell which you have and what is actually worth trying.
- Why are there lines on my monitor?Vertical or horizontal lines on a screen come from the panel, the cable or the graphics card. A full screen color test and two quick swaps tell you which.
- What to check the day a new monitor arrivesThe return window is worth more than the warranty and it closes. Here is the fifteen minute check to run before you decide to keep it.
Controller Test
Open the controller test- My controller isn’t being detectedMost undetected controllers come down to a charge-only cable, the wrong input mode or another application holding the device exclusively.
- Controller not working in Steam? How Steam Input changes thingsSteam Input can make almost any controller work in any Steam game and it can also cause double inputs or a stick that moves the mouse. Here’s how to set it up.
- Why isn’t my controller trigger registering a full press?A trigger that tops out below full travel makes cars crawl and guns misfire. The controller test shows the exact value from 0 to 1 so you can see where it stops.
- Controller works in browser but not in a gameCheck controller detection separately from game input support and mapping so you can troubleshoot a working browser test without guessing.
- Hall effect vs potentiometer sticks: is drift fixed for good?Hall effect sticks remove the part that wears out in a drifting controller. Here’s what they fix, what they don’t and whether a retrofit is worth it.
- How much stick drift is normal?Controller sticks never rest at exactly zero. Here is where the line sits between normal tolerance and a fault worth fixing.
- How to fix controller stick driftDrift is a worn potentiometer, not a software bug. Here is how to measure it, what actually fixes it and when a replacement module is worth it.
Refresh Rate Test
Open the refresh rate test- Why does my laptop drop to 60Hz on battery?A 120Hz or 144Hz laptop that falls to 60Hz when unplugged is usually saving power on purpose. Here’s how to confirm it and how to keep the higher rate.
- Is my monitor flickering because of FreeSync or G-Sync?Brightness flicker in dark scenes and loading screens is often variable refresh reacting to an unsteady frame rate. Here’s how to confirm it and stop it.
- My screen is tearing or stutteringTearing and stuttering look similar and have opposite causes. Telling them apart takes one question and the fix follows from the answer.
- Why is my 144Hz monitor running at 60Hz?High refresh monitors ship set to 60Hz and stay there until you change it. Here is that setting and what to check if changing it doesn’t stick.
Microphone Test
Open the microphone test- Why does my Bluetooth headset sound bad on calls?Music sounds fine until a call starts, then everything turns thin and muffled. That’s Bluetooth headset mode and there are two reliable ways around it.
- Why isn’t my headset mic working on my PC?Headphones work but the mic doesn’t. On a PC this is usually the plug type, the port you used or the input Windows picked. Here’s how to find which.
- My microphone isn’t working in the browserBrowser mic problems are usually permissions or device selection rather than hardware. Work through this in order to find which.
- My microphone sounds muffled or quietThin, distant or muffled audio is usually gain, position or a processing setting rather than a failing microphone. Here is how to tell which.
- Microphone works in browser but not in a meeting appUse a successful browser microphone test to narrow down meeting-app input selection, mute controls and permissions before replacing equipment.
- Why do people hear an echo on my calls?If others hear their own voice repeated back, your microphone is picking up your speakers. Here’s how to confirm it and stop it, from headphones to app settings.
Speaker Test
Open the speaker test- Why is my Bluetooth audio delayed?Wireless audio lag is the codec and the buffering, not a fault. Here is why it happens and which parts of it you can actually reduce.
- There is no sound coming from my speakersSilent speakers are usually the wrong output device or a muted mixer channel rather than broken hardware. Here is the order to check.
- Sound is only coming from one sideOne silent channel is usually a balance setting or a partly inserted plug rather than a dead speaker. Here is how to tell the difference.
- Why are my speakers crackling or popping?Crackle has several distinct causes and each one sounds slightly different. Identifying which you have narrows the fix considerably.
- What frequencies can you hear?Play tones from 50Hz to 20kHz and find the highest one you can hear. Here’s what the result means, what it doesn’t and why your speakers matter as much as your ears.
Webcam Test
Open the webcam test- Your camera is being used by another applicationThis error means something else is holding your camera. Here is how to find what has it, including the background apps nobody thinks to check.
- Why is my webcam showing a black screen?Work through a webcam black screen by checking the shutter, selected camera and app access before treating it as a hardware failure.
- Why does my webcam look blurry or grainy?Grain, softness and washed-out color are almost always lighting rather than a failing camera. Here is why and what actually improves it.
- Why is my webcam laggy or choppy?A choppy webcam is usually low light, USB bandwidth or the call connection rather than a failing camera. Measuring the local frame rate tells you which.
- Why is my webcam upside down or mirrored?A mirrored preview is usually deliberate and other people see you the right way round. An upside down picture is a driver or mounting issue. Here’s how to tell.
Not sure where to start?
If you know which device is misbehaving, go straight to its test. The guides are for the cases where the symptom is clear but the cause isn’t, which is most of them: a mouse that double clicks might be a worn switch or a setting and a camera that’ll not open is almost never broken hardware.
Every guide says which it is likely to be and none of them assume the answer is new hardware.
Hit a term you don’t recognize? The hardware glossary explains rollover, stick drift, refresh rate and the rest in plain English.
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