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How to check a used Oppo phone before you buy it

Updated September 27, 2026

Oppo sells a lot of phones, so the used market has everything from budget A-series models and camera-focused Renos to Find X flagships and Find N foldables. Most are straightforward, but you'll still meet Chinese-market imports, phones tied to the previous owner's Oppo account, and curved screens swapped for cheap replacements. This guide follows the order to check things in, and takes about 15 minutes. Realme and OnePlus phones run the same ColorOS base, so most steps apply to them too.

Tip: open soimay.com in Chrome on the phone you're checking. The steps that apply to every Android phone are in how to check a used Android phone; this guide covers what's specific to Oppo.

1. Oppo account and Google account

  • Oppo account (HeyTap): open Settings; the account line at the top must be empty. If an account is signed in, Find My Device can lock the phone after a factory reset.
  • Google account: go to Settings › Users & accounts (the name varies between ColorOS versions); none of the seller's accounts should be left.

The safest option is to have the seller sign out of both and factory reset in front of you, then sign in yourself.

2. Official or imported

  • Go to Settings › About device and check the model number. International models usually start with CPH (for example CPH2581). A number starting with P usually means a Chinese domestic model, which may lack Google services and some languages.
  • Dial *#06# to show the IMEI and compare it with the SIM tray and the box.
  • Oppo's support site in many countries lets you check the warranty by IMEI: an official warranty still running is a real plus.

3. Oppo's hardware test menu

On many ColorOS phones, dialling *#899# in the Phone app opens Engineer Mode, which includes a manual test for each part: screen, touch, speakers, microphones, sensors. The code doesn't work on every model; if nothing opens, skip it, the Soi Máy tests are enough.

Only use the test section, and don't change settings in Engineer Mode on someone else's phone.

4. The screen, especially curved ones

Reno and Find X phones often have curved AMOLED screens. They look great but are expensive to replace, so many used ones have had a cheaper replacement:

  • Step through the colours to spot dead pixels, green lines, tints, and burn-in on a grey screen.
  • Look closely at the curved edges: cheap replacements often have uneven brightness there and poor touch.
  • Enroll a fingerprint: non-original screens often make the in-display sensor slow or dead.
Dead pixel, backlight bleed and burn-in testFind dead or stuck pixels, backlight bleed, burn-in and lines on a phone or laptop screen. Eight full-screen colours, free, no app to install.

If the phone is sold with a 90 or 120 Hz screen, choose the highest setting in Settings › Display & brightness and measure the refresh rate.

5. Touch, especially at the edges

Fill the grid, paying attention to the cells along the edges of a curved screen: they're often dead after a screen replacement.

Touch screen test: dead zones and ghost touchesSwipe to fill a grid of cells and spot dead touch zones or ghost touches on a phone or tablet. Runs full screen, free.

6. Battery and SUPERVOOC charging

  • Newer ColorOS phones have Settings › Battery › Battery health, showing maximum capacity compared with new. Older phones may not have it.
  • Plug in the original charger and cable: the screen should show SUPERVOOC or VOOC. If it doesn't, the cable, charger or port has a problem, or the cable isn't original.
  • Run the battery test for a few minutes to see how fast it drains.
Battery and charging port testSee the battery level, catch a loose charging port by plugging in and out, and watch how fast it drains. Plus where to read battery health.

7. Cameras

Renos are sold on their cameras, so test them properly:

  • Open each camera in the camera test and in the Camera app: ultra-wide, main and telephoto if there is one. Shoot something close to check focus speed.
  • Record a few seconds of video and play it back: shaking while the phone is still points to a faulty stabilisation unit.
  • Check the camera glass: a small crack makes photos hazy or full of glare against the light.

8. Find N foldables

Foldables need a few extra checks:

  • Open and close it slowly a few times: the hinge should feel even, not rattle, and open fully flat.
  • Look at the crease under a light: a slight crease is normal, but a peeling protective layer, bubbles or dead pixels along the fold are faults.
  • Run the touch and screen tests on both the inner and outer screens.

9. Speakers, microphone, signal

Try the speakers and microphone, make a call on your own SIM, and try mobile data and Wi-Fi.

When you're done

Save the results as a PDF or a link and QR code on the Results page. The things you check by eye (accounts, IMEI, model number) are in the manual checklist.

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