Phone Repair Guides

Smartphone troubleshooting knowledge base

Phone Repair Guides

Practical first-step checks for iPhone, Samsung Galaxy, Google Pixel and other Android phones. Work through the safe checks first, protect your data, and learn when the fault is more likely to need a replacement part or hands-on diagnosis.

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Protect the phone and your data before deeper troubleshooting.

If the phone is swollen, very hot, wet, badly bent, smells unusual, has a damaged charging port, or contains data you cannot replace, stop repeated charging and restart attempts. Back up important data as soon as the phone is stable enough to do so. Do not factory-reset a phone until you understand what will be erased.

Choose the symptom

Start with what the phone is doing

Most phone faults fall into a few groups: power, charging, battery, display, touch, liquid, software, storage, network, audio, camera or physical damage. These guides help narrow the cause before parts are replaced.

01

Power

Phone won't turn on or the screen stays black

A flat battery, failed charger, frozen operating system, damaged screen, battery fault or board problem can all look like a completely dead phone.

Start with simple checks

  1. Connect a known-good compatible charger and cable to a working wall outlet.
  2. Leave a deeply discharged phone connected for at least 15 to 30 minutes before assuming it is dead.
  3. Check for vibration, sounds, notifications or a computer detecting the phone. If the phone reacts but the screen stays black, the display may be the real fault.
  4. Remove accessories or cases that may be holding a button down.
  5. Try the correct force-restart method for the model.

Common force-restart methods

  • Recent iPhones / iPhone 8 and later: quickly press Volume Up, quickly press Volume Down, then hold the Side button until the Apple logo appears.
  • iPhone 7 / 7 Plus: hold Side and Volume Down until the Apple logo appears.
  • iPhone 6s and earlier: hold Home and Side/Top until the Apple logo appears.
  • Many Samsung Galaxy phones: hold Side/Power and Volume Down until the phone restarts. Button combinations can vary by model.
  • Google Pixel: hold the Power button for an extended period if a normal press does not respond.
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Rings or vibrates but shows no picture?

That is a strong clue that the phone itself may be running and the fault is in the screen, display connector or related circuitry rather than the entire device being dead.

02

Charging

Phone is not charging, charges slowly or only charges at an angle

Charging faults often come from the cable, power adaptor, debris in the port, moisture detection, battery condition, temperature, worn connectors or charging circuitry.

  1. Try a known-good compatible cable and wall charger.
  2. Try the charger on another device to confirm the charger itself works.
  3. Inspect the phone's port with a light. Pocket lint can stop the plug seating fully.
  4. Do not scrape the port with metal objects. If debris is compacted or the connector is loose, arrange proper port cleaning or inspection.
  5. Remove the case and check that the cable can insert fully.
  6. If the phone supports wireless charging, test it. Wireless charging working while wired charging fails helps narrow the fault toward the port or wired charging path.
  7. Let a hot phone cool before retesting. Phones may reduce or stop charging when temperature is outside the normal range.
  8. Check for a moisture or liquid warning. Do not override it unless the manufacturer specifically provides an emergency option and the situation truly requires it.
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Stop if the port gets very hot, smells burnt, is visibly corroded or the cable only works when forced sideways.

Continuing to use a damaged connector can make a port or board fault worse. A charging-port replacement, flex assembly, battery or board-level charging repair may be needed.

03

Battery

Battery drains quickly, shuts down early or is swelling

Battery ageing, high screen use, poor signal, background apps, heat and a physically worn battery can all reduce run time.

Before replacing the battery

  • Restart the phone.
  • Check Battery settings for apps using unusual amounts of power.
  • Install pending system and app updates.
  • Check whether the problem began after installing a specific app.
  • Test with normal brightness and without constant hotspot, GPS, gaming or video use.
  • On iPhone, review Battery Health where supported. On Android, available battery-health information varies by brand and model.

Signs the battery itself may be worn

  • Percentage falls rapidly even with light use.
  • Phone shuts off while showing charge remaining.
  • Battery percentage jumps after restarting.
  • Phone only stays on while connected to power.
  • Battery health reports severe degradation.
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Swollen battery = stop using the phone.

If the screen or back cover is lifting, the phone is bulging, or the battery has expanded, stop charging it. Do not press the screen/back down, puncture the battery, or keep it in a hot area. Arrange battery replacement or safe handling.

04

Display

Cracked screen, black display, lines, flicker or ink-like marks

Visible glass damage is not the only screen fault. OLED/LCD damage can cause black areas, coloured lines, flashing, green/white screens or a completely blank display.

  • If the image is normal and touch works, damage may be limited to the outer glass on some assemblies, but many modern phones are repaired by replacing the complete display assembly.
  • If the phone rings or vibrates but shows no image, test brightness and force restart before assuming the phone is dead.
  • Vertical lines, black spreading patches, flashing or colour distortion after impact usually point to panel damage.
  • A screen that works only when twisted or pressed can indicate connector or board damage and should not be repeatedly flexed.
  • If the screen is lifting with no obvious impact, check for battery swelling before replacing the display.

Screen damage still present?

Send us the exact model and a photo of the damage. Screen availability and price depend on the model and the quality option required.

Request a Screen Quote
05

Touch

Touchscreen is unresponsive, taps by itself or has dead areas

Ghost touch and dead zones can come from a damaged screen, moisture, a poor-quality screen protector, software, charger interference or a failing touch layer.

  1. Clean and dry the screen.
  2. Remove a damaged or badly fitted screen protector and case.
  3. Disconnect the charger and test again. Faulty charging accessories can sometimes cause erratic touch behaviour.
  4. Restart the phone.
  5. Test whether the fault happens in every app and on the lock screen.
  6. If the problem began after a drop or screen replacement, the display assembly or connector should be inspected.
06

Liquid damage

Phone got wet or shows a moisture warning

Water resistance is not the same as waterproofing, and seals can weaken with age, impact or previous repairs. Salt water, drinks and other liquids can be much more damaging than clean water.

  1. Disconnect the charger and accessories immediately.
  2. If the phone is not designed for continued operation while wet and you suspect internal liquid entry, power it off when safe to do so.
  3. Remove the case and wipe the exterior with a clean, dry cloth.
  4. Keep the charging port facing down and allow the phone to dry in a cool, ventilated area.
  5. Do not apply heat, use a hair dryer or put the phone in rice.
  6. Do not insert cotton buds, paper or metal tools into the charging port.
  7. If the phone was submerged, exposed to salt water/drinks, has camera fogging, distorted sound, charging problems or intermittent faults, arrange inspection even if it appears to recover.
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Liquid faults can worsen after the phone appears to recover.

Corrosion can continue around connectors and board components. If the data matters, avoid repeated power testing and prioritise backup or professional inspection.

07

Temperature

Phone gets unusually hot or stops charging

Gaming, camera use, navigation, poor reception, fast charging and hot weather can make phones warm. Persistent heat during light use can point to software, battery, charging or board faults.

  • Remove the case temporarily and stop heavy apps.
  • Disconnect charging if the phone is uncomfortably hot.
  • Move the phone out of direct sun or a hot vehicle and let it cool naturally.
  • Restart it after it reaches a normal temperature.
  • Check Battery settings for an app using excessive power.
  • Replace damaged chargers/cables rather than continuing to test them.
  • If the heat is concentrated around a swollen battery, burnt charging port or damaged area, stop using the phone and arrange repair.
08

Performance

Phone is extremely slow, freezes or lags

Low storage, a problem app, background syncing, heat, an ageing battery, software corruption or failing storage can all make a phone feel much slower than normal.

  1. Restart the phone.
  2. Check free storage. Phones with almost no free space can struggle to update, cache files and run apps.
  3. Update the operating system and apps.
  4. Check whether one app is using abnormal battery, memory or background data.
  5. Remove apps you no longer use.
  6. Test after the phone has cooled if the lag happens while hot.
  7. On Android, Safe Mode can help show whether a third-party app is causing the problem. The Safe Mode method varies by manufacturer.
  8. Do not factory reset until your photos, messages, authenticator access and other important data are backed up.
09

Storage

Phone storage is full

A full phone can stop camera recording, block updates, prevent apps from saving data and make the operating system unstable.

  • Open the phone's Storage settings and identify the largest categories first.
  • Back up photos and videos before deleting them.
  • Empty Recently Deleted / Trash only after confirming the backup exists.
  • Clear downloaded movies, podcasts and offline music you no longer need.
  • Remove unused apps rather than deleting unknown system folders.
  • Check messaging apps for large attachments and duplicate media.
  • If using cloud photo services, understand the difference between deleting from the device and deleting from the cloud account before confirming deletion.
10

Software

Apps crash, settings fail or the phone behaves strangely

If only one app fails, the app is more likely to be the issue. If many apps and system menus fail, look at storage, updates and the operating system.

  1. Restart the phone.
  2. Update the affected app.
  3. Update the phone's operating system.
  4. Check that storage is not critically low.
  5. Force close and reopen the app.
  6. On Android, clearing an app's cache may help. Clearing app data can sign you out or erase local app content, so read the warning first.
  7. Reinstall the affected app only after confirming its data is synced or backed up.
  8. If the whole phone is unstable, back up data before considering a reset or operating-system restore.
11

Startup

Phone is stuck on the Apple, Samsung, Google or manufacturer logo

A boot loop can be caused by failed updates, full storage, damaged system files, a bad battery, failed storage, liquid damage or board faults.

  1. Force restart once using the correct method for the model.
  2. Connect a known-good charger and allow time for a very low battery to recover.
  3. Remove unnecessary USB accessories.
  4. If the phone can enter recovery mode, use the manufacturer's update/repair option before choosing an erase/reset option where possible.
  5. If your data is important, do not keep selecting restore, factory reset or erase options without understanding the data loss.
  6. If the boot loop began after impact, liquid exposure or battery swelling, hardware inspection should come before repeated software restores.
12

Connectivity

Wi-Fi, Bluetooth or mobile data is not working

First determine whether the problem is one phone, one network, one accessory or the mobile carrier.

Wi-Fi / Bluetooth

  • Toggle the connection off and on.
  • Restart the phone and router/accessory.
  • Forget and reconnect to the Wi-Fi or Bluetooth device.
  • Test another Wi-Fi network or Bluetooth accessory.
  • Install pending system updates.

Mobile data

  • Check Airplane Mode is off.
  • Confirm mobile data is enabled for the active SIM/eSIM.
  • Restart the phone.
  • Check carrier outages or account restrictions.
  • Test the SIM in another compatible phone where practical.
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Reset Network Settings is a deeper step.

It can remove saved Wi-Fi networks, Bluetooth pairings and network settings. Use it only after the basic checks and make sure you know the Wi-Fi passwords you need.

13

Speaker

No sound, distorted sound or the speaker is very quiet

Blocked speaker mesh, Bluetooth routing, water, software settings or a damaged speaker can all affect sound.

  1. Raise media and ringtone volume.
  2. Turn Bluetooth off temporarily to make sure audio is not being sent to another device.
  3. Remove a case that covers the speaker openings.
  4. Inspect the speaker mesh for dirt without pushing sharp objects through it.
  5. Restart the phone.
  6. Test calls, music and speakerphone separately. Different audio paths can use different speakers.
  7. If the problem followed liquid exposure, allow the device to dry and consider inspection if distortion remains.
14

Microphone

People cannot hear you, recordings are muffled or call audio cuts out

Modern phones often use several microphones, so one app or call mode can fail while another still works.

  1. Remove the case and check that microphone openings are not blocked.
  2. Record a voice memo and play it back.
  3. Record video with front and rear cameras and compare the sound.
  4. Test a normal call and speakerphone call.
  5. Disconnect Bluetooth headsets and car systems while testing.
  6. Check microphone permission for the affected app.
  7. If one microphone path consistently fails after impact or liquid exposure, hardware inspection may be needed.
15

Camera

Camera is blurry, shaking, won't focus or shows a black image

A dirty lens, case interference, app fault, stabilisation damage or failed camera module can cause camera problems.

  • Clean the camera glass with a soft lens-safe cloth.
  • Remove magnetic accessories, lens protectors or cases that interfere with the camera.
  • Restart the phone and test the built-in camera app.
  • Switch between front, rear and zoom lenses to identify whether only one module fails.
  • Test focus on a well-lit subject at a normal distance.
  • Persistent shaking, clicking, failure to focus or a black image on one lens after impact can point to a damaged camera module.
16

Security sensors

Face ID, face unlock or fingerprint recognition stopped working

Dirty sensors, screen protectors, software, prior screen work, impact and damaged biometric hardware can all affect unlocking.

  1. Clean the screen/sensor area and remove anything covering it.
  2. Restart the phone.
  3. Install pending system updates.
  4. Delete and re-enrol the fingerprint or face profile only if the phone allows it and you know the device passcode.
  5. For under-display fingerprint sensors, test without a thick or incompatible screen protector.
  6. If the fault began after screen, camera or board repair, the biometric system may need model-specific diagnosis. Some security components are paired to the original device and cannot be treated like ordinary interchangeable parts.
17

Carrier

No SIM, SOS only, no service or eSIM problems

Carrier outages, account issues, SIM damage, settings, antenna faults and board damage can all cause loss of mobile service.

  1. Toggle Airplane Mode on for a short time, then off.
  2. Restart the phone.
  3. Check the carrier for outages and confirm the account is active.
  4. If using a physical SIM, remove and reseat it only when the tray and phone are dry and undamaged.
  5. Test another known-good compatible SIM if available.
  6. For eSIM, do not delete the eSIM profile unless you know how it will be reactivated.
  7. If the phone was dropped, bent or liquid-damaged and service disappeared afterwards, antenna or board diagnosis may be needed.
18

Protect your data

Back up the phone before repair, reset or replacement

Photos, messages, authenticator apps, notes and app data can be more important than the hardware itself.

  • Make a current iCloud, Google or manufacturer backup where supported.
  • Confirm important photos/videos have finished uploading before deleting local copies.
  • For irreplaceable files, consider a second copy on a computer or external storage as well as cloud backup.
  • Make sure you know the Apple Account / Google Account details and device passcode before a reset.
  • Check authenticator apps and banking apps before moving to another phone. Some require their own transfer or recovery process.
  • Do not erase a phone with a failing screen, storage fault or board issue if the goal is data recovery.

Need data from a damaged phone?

Tell us whether the phone powers on, whether the screen works, and what data matters most. The best repair path can be different when data recovery is the priority.

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When basic troubleshooting is not enough

Signs the phone is more likely to need repair

Once simple charger, restart, settings and software checks have been ruled out, these symptoms often point to a part or internal hardware fault.

01

Screen or touch hardware

Lines, black OLED/LCD areas, no image with a working phone, ghost touch after impact, or a cracked display usually needs screen diagnosis or replacement.

02

Battery or charging hardware

Swelling, rapid shutdowns, loose charging ports, heat at the connector, or wired charging failure with known-good accessories can require parts or board-level diagnosis.

03

Liquid or impact damage

Corrosion, camera fogging, intermittent faults, bent housings and broken connectors should be inspected before repeated charging or power testing.

04

Board or storage fault

No power after known-good charging, persistent boot loops, missing baseband/service, or a phone that repeatedly disappears from a computer can require deeper diagnosis.

Prestige Mobile Solutions

Still having trouble with your phone?

Send us the exact make and model, the symptoms, whether there was any drop or liquid exposure, and what you have already tried. We can help work out whether the next step is software troubleshooting, a replacement part, data recovery or hardware diagnosis.

Request Phone Help