[SOLVED] I'm looking for Huawei Y3II repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Huawei Y3II. 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.

@Rodolfo

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 Huawei Y3II 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/Guide/Motorola+Atrix+HD+Front+and+Rear+Camera+Replacement/53491
Take a look at comment #350
Also, this : https://www.ifixit.com/Answers/View/700153/iPad+stuck+in+update+mode,+can%E2%80%99t+even+get+in+dfu+mode.
You can also check this video starting from minute 2:

The Huawei Y3II 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 Huawei Y3II 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 Huawei Y3II 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 Huawei Y3II 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/372651/Printer+Driver+not+working+with+El+Capitan

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

Action: Contact your cellular carrier or check your data plan details. Current Regulation: The backlight IC monitors the current through the LEDs (via the sense resistor) and adjusts its switching frequency/duty cycle to maintain the desired current, which in turn controls the brightness. You will need a specific set of tools and a compatible replacement part for this repair: If that doesn't work, try holding Power + Volume Down, or Power + Volume Up (combinations vary by manufacturer). Motherboard damage (scratched traces, heat damage) during micro-soldering. The right tools and safety precautions are essential for successful and safe storage preparation. Improper Reassembly: If a phone has been opened previously, misplaced screws, trapped cables, or incorrect component seating can interfere with antenna performance. Readings significantly higher (e.g., 50mA, 100mA, or more) indicate excessive leakage. Bluetooth: Is the accessory charged and working? Is it within range? Try pairing with a different Bluetooth device. Also, test other phone functions to ensure no components were accidentally dislodged during the repair. Once all solder points are molten, the shield should lift off cleanly. If all outputs are dead or distorted, it points more strongly to the main audio amplifier IC. Android: While Android doesn't have a universal, explicit "battery health" indicator like iOS, some OEM skins (e.g., Samsung's Device Care) might show battery temperature or provide warnings. Analyzing smartphone haptic feedback failures requires a methodical approach to distinguish between software glitches, settings misconfigurations, and underlying hardware defects. When this unit fails, the screen may appear completely black, extremely dim, or exhibit uneven lighting, even though the phone itself might be fully functional and responsive to touch. Tiny rubber gaskets around ports and buttons can become dislodged, damaged, or lost. A lack of output voltages or unstable readings can indicate a faulty PMIC or a short on one of its output lines. Flex Cable: If the port is on a flex cable, inspect the cable itself for tears, kinks, corrosion, or burnt spots. Identification: Misidentifying the IC can lead to wasted effort and further damage. Among these, a broken trace , a thin conductive copper pathway that connects components , can render a device inoperable. Cleaning Method: Use a non-conductive tool like a wooden toothpick, a plastic flosser, or a thin plastic pick to gently dislodge any compacted debris. You can then systematically uninstall recently added apps to identify the culprit. Capacitors: Used for filtering, smoothing voltage ripples, and stabilizing the power rails. Diagnosing poor audio during video playback requires a systematic approach, carefully ruling out common software and settings issues before considering hardware faults. If cleaning the port didn't work and wireless charging does work, the physical charging port assembly itself, or the flex cable connecting it to the motherboard, is the most likely culprit for wired charging failures. Melted Solder Joints: Solder joints near hot spots might appear dull, reflowed, or even slightly melted, indicating they reached their melting point. Lack of Regulation: In many regions, regulations against counterfeit electronics are weak or poorly enforced. This consistency makes it relatively straightforward, but it still requires careful attention to detail and an understanding of its implications. Repairing a faulty PMIC requires advanced micro-soldering skills and specialized equipment, usually beyond the scope of a beginner. Flashing Tool Errors: Ensure the firmware matches your device model exactly.

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