Built-in diagnostics vs. a browser hardware test
Most phones and laptops include a manufacturer hardware test. They're good at finding failed memory, drives, batteries and disconnected parts, but they're often hidden behind secret codes or startup keys, blocked on carrier phones, or missing after a reset. They also rarely check what you notice day to day: a single dead key, a touch dead zone, a crackling left speaker, a blurry webcam or slow Wi-Fi.
The free phone diagnostic and laptop test work on every brand in the browser and cover those everyday parts, with a report you can share. Use both: the built-in test for deep hardware faults, and the browser test for everything you touch, see and hear.
Quick reference: how to open each brand’s test
- Samsung Galaxy: dial *#0*# in the Phone app, or Samsung Members › Support › Phone diagnostics.
- iPhone: no hidden test menu. Settings › Battery › Battery Health, and Settings › General › About › Parts and Service History for replaced parts.
- Google Pixel: dial *#*#7287#*#* for the Pixel Repair and Diagnostic app on recent models, or check Settings › Battery › Battery health.
- MacBook: Apple Diagnostics: on Apple silicon hold the power button until startup options appear, then press Command-D; on Intel Macs hold D while starting up.
- Dell: press F12 at startup and choose Diagnostics, or use SupportAssist in Windows.
- HP: press Esc at startup, then F2 for HP PC Hardware Diagnostics UEFI.
- Lenovo: the hardware scan in Lenovo Vantage, or the Lenovo Diagnostics tool, which also runs from a USB drive when Windows won’t start.
- Surface, ASUS and Acer: the Surface app and Surface Diagnostic Toolkit, MyASUS System Diagnosis, and Acer Care Center checkup.
- Any Windows laptop: powercfg /batteryreport, mdsched for memory and Reliability Monitor.
- Chromebook: the Diagnostics app in the launcher, and battery_test in crosh (Ctrl + Alt + T).
Each guide above has the full steps, what the results mean, and what else to check when the menu is blocked.
Before you buy a used phone or laptop
A built-in test only tells you about the hardware. When you buy second-hand, also check that the device isn’t locked to the seller’s account (iCloud, Google, Microsoft or a school or company), that the IMEI isn’t blacklisted with the free IMEI checker, and that the battery isn’t worn out. The used phone checklist and used laptop checklist list every step. If you can’t meet the seller, a live remote inspection lets you watch the tests run on their device before you pay.
Frequently asked questions
How do I run a hardware diagnostic on my phone?
Samsung Galaxy phones have the *#0*# test menu and Samsung Members diagnostics, Google Pixel has the Pixel Diagnostic app, and iPhone reports battery health and replaced parts in Settings. For any brand, open mxmob.com/check in your phone’s browser to test every component.
How do I run hardware diagnostics on a laptop?
Macs have Apple Diagnostics (hold power then Command-D on Apple silicon, or D on Intel), Dell has pre-boot diagnostics with F12, HP has F2 diagnostics after pressing Esc, and Lenovo, ASUS and Acer have apps with hardware checks. For any laptop, open mxmob.com/laptop-test in the browser.
Are hidden diagnostic codes safe to use?
The codes in these guides only open test or information screens and don’t change settings. Avoid codes from unknown sources, since some reset settings or open engineering menus.