[SOLVED] I'm looking for Wiko Jerry repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Wiko Jerry. It's started acting up, and I'm looking for a detailed service manual with boardviews and schematics to properly diagnose and repair it. I need to take precise voltage measurements around the board, so having the right documentation would be very helpful.

Thanks in advance for your help.

Selected Answer

I actually found that service manual on a tech Discord server a while back. A really helpful member there shared a direct link to their blog and I've saved it. I'm happy to pass it along here. Hopefully, these boardviews and schematics help you fix your phone, just like they got me through my repair. Looks like we have the same model.

@Nicholas

Absolute legend! That's exactly the info I was searching for. This is going to save me so much time probing in the dark. Seriously, thanks a ton for sharing the link!

Hi there,

I also have the Wiko Jerry and just downloaded the manual you shared. I'm pretty new to board-level phone repair, and this is a bit intimidating with all the tiny test points and the schematics. Could you point me in the right direction on how to start troubleshooting this ? Any advice on the first few things I should check would be a massive help.

Thanks so much for your time

General advices: start by checking the voltage at the battery connector on the board. With a known-good battery connected, you should see a steady voltage between 3.7V and 4.2V. After that, a great next step is to check the main power management IC (PMIC) for shorts. Using your multimeter in diode mode, check for shorts on the large input capacitors surrounding the PMIC.

Here are a few useful references for troubleshooting your device:
https://www.ifixit.com/Answers/View/260057/What+is+proper+temp+setting+for+GE+freezer-refrigerator
Take a look at comment #769
Also, this : https://www.ifixit.com/Wiki/Garmin_Dezl_760LMT_Troubleshooting.
You can also check this video starting from minute 6:

The Wiko Jerry service manual and boardviews from the link above were exactly what I've been searching for. I couldn't find a complete, free copy anywhere else. Seriously, thank you for sharing this you're a lifesaver!

Hi everyone, I'm working on a Wiko Jerry with a no power issue and need some guidance with my measurements.
I'm detecting 3.3V on the VREG_MAIN line (pin 1 of the PMIC), which looks good, but I'm getting 0V on the VDD_CPU line (pin 8) where the schematics indicate I should see about 0.9V.
Since this is a core voltage for the application processor, could this missing rail be why the device shows no signs of life?
What's the best procedure to diagnose this further? Should I check for shorts on the CPU rail first, or look at the PMIC's enable signals?
I've already verified the main 3.3V and 1.8V power rails are present and stable.

My Wiko Jerry was working perfectly until yesterday when it suddenly went completely dead. Now it won't respond to the power button, doesn't vibrate, and shows no signs of life even when connected to a charger. I'm worried there might be a serious issue.

I have a decent multimeter, a basic soldering iron, and a healthy dose of patience. While I've successfully replaced iPhone batteries and charging ports, this will be my first attempt at actual diagnosis. The sheer density of BGA chips and microscopic components is honestly a bit overwhelming.

I'm particularly curious about the alcohol trick I've seen online where you apply isopropyl to the board and look for evaporation hotspots to locate shorts. Is this actually a reliable method for beginners, or are there better approaches I should try first with just a multimeter?

I learned this lesson the hard way last month with mine, it was declared "dead" by two different shops. The phone showed absolutely no signs of life - no charging indicator, no vibration, nothing. Before diving into complex board work, I decided to try one more basic test: wireless charging.

To my complete surprise, it actually heated up on the charging pad! This single discovery completely changed my diagnostic path. It turned out the issue wasn't with the main board or processor, but with the notoriously fragile USB-C port that had failed completely. A $15 replacement part and some careful soldering brought it back to life.

The moral? Always exhaust every external testing method before opening the device. Test wireless charging if available, try different charging methods, and don't assume the worst case scenario. Sometimes the most "dead" devices have the simplest solutions hiding in plain sight.

I suspect my issue might be related to that cheap, third-party fast charger I used at the airport last week... Now the device gets extremely hot during charging, the screen flickers at low brightness, and sometimes it randomly shuts down at 30% battery. Could this have damaged the power management IC or battery calibration?

If your Wiko Jerry starts acting up, random reboots, fast battery drain, or connectivity issues, there are several diagnostic steps you can take before assuming the worst:

• Check your charging habits: Using poor-quality chargers or wireless pads can gradually damage your battery and charging circuit, leading to unpredictable behavior.
• Inspect the physical components: A slightly damaged charging port, worn battery, or even accumulated pocket lint can cause issues that seem like major hardware failures.
• Monitor temperature patterns: If your phone gets unusually hot during specific tasks (like camera use or gaming), it could point to a failing component rather than a software issue.
• Use diagnostic tools wisely: Ampere for battery health, phone diagnostic codes (*#0*# on many models), and a thermal camera can reveal problems without opening the device.
• Know when to stop: If you see liquid damage indicators tripped or smell burnt electronics, it's time to consult a professional before causing irreversible damage.

Also visit this link it may help : https://www.ifixit.com/Answers/View/826548/Slipping+clutch+maybe+because+of+loss+of+viscosity

Here's what I discovered on forums and technical databases:

Reflow/Replace Touch IC: If all other checks point to the touch controller IC as the fault, and it's a discrete chip on the motherboard, an advanced technician might attempt to reflow it with a hot air station. Power off both your phone and the problematic Bluetooth accessory, wait a minute, then power them back on. Peel Carefully: Using a plastic spudger or fine tweezers, carefully and slowly peel the old flex cable away from the frame or component it's attached to. Poorly performed repairs are a common cause of compromised water resistance. It's always better to start lower and gradually increase if the solder isn't melting. Reset Network Settings: Go to settings -> system -> reset options -> reset Wi-Fi, mobile & Bluetooth (Android) or General -> Transfer or Reset iPhone -> Reset -> Reset Network Settings (iOS). GApps Compatibility: If flashing a custom ROM, ensure you use the correct GApps (Google Apps) package compatible with the Android version of the ROM and your device's architecture (e.g., ARM64). Power Off and Disconnect Battery: Always ensure the smartphone is completely powered off, and the battery is disconnected to prevent short circuits and component damage during testing. Specific Component Failure: If the inductor supplies power to a particular IC (e.g., Wi-Fi module, audio codec), that component will not function. Calibration Error: During manufacturing or after a screen replacement, the digitizer might be improperly calibrated, leading to a persistent offset. Any remaining underfill residue on the pads or between them must be meticulously removed. Use a strong light source (e.g., a flashlight) and a magnifying loupe (10x-30x) or a stereomicroscope to examine it. You'll need to download the correct firmware for your specific phone model and region, place it on an SD card or external storage if your recovery allows, and then select the "Install" or "Apply update from SD card" option. If your phone has a metal or plastic frame surrounding the camera glass, you'll need to work within those confines. Check Storage: Full internal storage can significantly degrade performance. Their location and design vary significantly between manufacturers and models, which is why sourcing the correct replacement part and consulting a model-specific repair guide is paramount. Scalpel/Hobby Knife (e.g., X-Acto, Olfa): For scraping solder mask and precise cutting. A side-mounted fingerprint sensor typically consists of a small capacitive sensor module and a flexible printed circuit (FPC) cable. If a new haptic engine doesn't solve the problem, the issue is likely with the haptic driver IC (integrated circuit) on the motherboard, or a power/data line leading to it. Pairing/Serialization: Modern smartphones, especially flagship models, heavily serialize components. Repeat the diagnostic tests performed earlier (call test, voice memo, video recording) to confirm that the microphone issue is resolved and noise cancellation is working correctly. Examples: Tools that unlock bootloaders (e.g., via Fastboot commands on some devices), then allow flashing custom ROMs or modified modem firmware. Inject Voltage (Carefully!): If a short is found, connect a current-limited DC power supply (low voltage, e.g., 1V, 1A) to the shorted rail and use a thermal camera (as described in Topic 1) to locate the hotspot. Using a hot air rework station, set to an appropriate temperature (e.g., 300-350°C, adjust based on board/solder type) and low airflow, carefully heat the connector until the solder reflows. Use a suction cup and pry tools (plastic picks) to gently separate the back cover from the frame. After the battery is disconnected, the immediate risk of thermal runaway is greatly reduced, but it's not entirely eliminated, especially if the battery is swollen. Failed software update: An incomplete or corrupted OS update is a very common cause. Clamps or Rubber Bands: To hold the new panel in place while the adhesive cures. By proactively implementing and enforcing these measures, repair shops can build a reputation for reliability and trustworthiness, ensuring customer confidence and securing their own business against significant risks.6. Wi-Fi Analyzer Apps: These apps (Android) visualize Wi-Fi networks in your area, showing their channels and signal strengths, helping identify crowded channels or interference from neighboring networks.

@Desiree, Not sure what you're trying to say but ok :)