Diagnostics guides — page 2
Step-by-step fault finding for dead, shorted and half-working laptop boards.
- Diagnostics
Laptop Memory Errors and Beep Codes: Board-Level Causes
How to trace laptop memory errors and beep codes to the board: SO-DIMM checks, memory rails, SPD, slot damage, soldered RAM and why first boot can take minutes.
- Diagnostics
Laptop Liquid Damage Repair: What to Check First
What to do with a liquid-damaged laptop: immediate steps, safe disassembly, cleaning, where corrosion usually hits, and the order of checks before applying power.
- Diagnostics
Laptop Keyboard Not Working: Board-Level Causes
How to find board-level causes of a dead laptop keyboard: the keyboard matrix, the EC, connector and flex checks, liquid damage, and diode-mode line comparison.
- Diagnostics
Laptop Fan Not Spinning: Circuit Diagnosis
How to find why a laptop fan does not spin: testing the fan itself, the 5 V supply and fuse, PWM and tach signals, EC control and temperature sensor faults.
- Diagnostics
Laptop Dead After a Power Surge: What Usually Fails
What fails when a laptop dies after a power surge: the input chain, charger IC, system rail parts, and ports used as entry points, and how to assess the damage.
- Diagnostics
Laptop Charges Only When Turned Off
Why a laptop charges only when it is turned off: adapter power budget, input current limits, adapter ID, battery temperature, charge settings and charger faults.
- Diagnostics
Laptop Stuck in a Boot Loop: Hardware Causes
Hardware reasons a laptop restarts over and over before or during boot: memory, BIOS and ME problems, power-good glitches, weak regulators, heat and peripherals.
- Diagnostics
Laptop Audio Not Working: Codec and Amplifier Checks
How to diagnose laptop audio faults at board level: codec detection, the HD Audio bus, codec power, speaker amplifiers, EAPD, jack sensing and speaker wiring.
- Diagnostics
How to Find a Short Circuit on a Laptop Motherboard
A complete method for finding shorts on laptop boards: confirming the short, splitting the rail, voltage injection, locating the warm part and confirming the fix.
- Diagnostics
Finding Shorts with Freeze Spray, Thermal Camera and Rosin
Three ways to spot the shorted part on a laptop board during voltage injection — thermal camera, freeze spray and rosin — and when each one works best.
- Diagnostics
External Monitor Works but the Laptop Screen Is Black
External monitor works but the laptop screen is black: separating backlight from image faults, panel power, eDP signals, cables, lid sensors and the display path.
- Diagnostics
Charger LED Goes Off When Plugged In: Finding the Short on DCIN
Why a laptop charger's LED goes off when plugged in: a short on the input rail, and how to find it — TVS diodes, input capacitors and MOSFETs, and the DC jack.