[SOLVED] I'm looking for VPLUS M5509 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my VPLUS M5509. 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.

@Edward

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 VPLUS M5509 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/277528/Screen+only+works+when+pressed+on+at+certain+spots
Take a look at comment #1738
Also, this : https://www.ifixit.com/Answers/View/358297/boot+fail,+fan+spin,+black+display.
You can also check this video starting from minute 9:

The VPLUS M5509 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 VPLUS M5509 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 VPLUS M5509 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 VPLUS M5509 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://xdaforums.com/t/downgrade-note-3-sm-n9005-from-android-5-0-to-4-4-4.3184942/

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

Micro-soldering allows for the repair of individual faulty components (e.g., a charging IC, a shorted capacitor, a broken connector), saving the user money and potentially preserving data. Disconnect from Logic Board: Carefully use tweezers or a plastic spudger to pry open the ZIF connector lock (if applicable) and gently slide out the flex cable, or simply pry up the snap-on connector. Go to Settings -> System -> Reset options -> Erase all data (factory reset) (Android) or Settings -> General -> Transfer or Reset iPhone -> Erase All Content and Settings (iOS). Understanding the signs and causes of motherboard flexing is crucial for accurately diagnosing persistent, intermittent phone malfunctions and determining whether a repair is feasible or if a replacement is the more practical solution.10. Without them, even the most experienced technician faces a significantly higher barrier to successful diagnosis and repair, underscoring the importance of contextual understanding in advanced smartphone board repair.8. At this point, unless you have advanced repair skills, professional repair is often the best course of action. A damaged flex cable is a very common cause of unresponsive power buttons. Monitor Battery Usage Stats: This is your most powerful diagnostic tool. "Bricked" Device: If your phone is already unbootable, data recovery becomes a much more complex and often expensive process, potentially involving specialized data recovery services that work directly with storage chips. These bands are allocated differently across countries and even by different carriers within the same country. Wi-Fi and Bluetooth Still Working: This helps differentiate a baseband issue from a more general logic board or Wi-Fi module fault, as Wi-Fi/Bluetooth are typically handled by separate chips. Heat Gun or Hair Dryer: To soften adhesive for the screen or rear panel removal. A non-responsive touch screen is one of the most frustrating and debilitating issues a smartphone user can encounter. Does the screen brightness fluctuate erratically or stay too dark/bright for the ambient conditions? (Ambient Light Sensor) Ultimately, diagnosing issues related to overclocking or custom kernels is a process of elimination. Localized Bright Spots (Hot Spots): These appear as distinct, brighter-than-normal patches. What you initially perceive as trapped dust might simply be external dirt. Fine-tip Tweezers: For handling small screws and delicate flex cables. Recovery Mode: A special boot mode that allows users to perform system maintenance, such as installing updates, clearing caches, or performing factory resets. Malware or Viruses: To remove persistent malware that cannot be otherwise eradicated. Inspect again under the microscope to ensure no shorts are created and the wire is secure. Here is a detailed, systematic guide to diagnose and fix a smartphone with an "invalid battery" message: Use a Protective Case: A good case can absorb shock and protect your phone from impacts. The proximity sensor flex cable is usually located at the very top of the display assembly, often integrated with the front camera and earpiece speaker. Even a slight misalignment can impact Face ID's ability to map your face. With Another Charger: If you have access to a different, known-good wireless charging pad, try charging your phone on it. Probe from the jumper wire to adjacent ground points, power rails, or other traces to ensure no unintended connections have been made. Loudspeaker Module/Charging Port Assembly: The S Pen slot flex cable is frequently integrated with or connected to the charging port assembly or the loudspeaker module, which usually sits at the bottom of the phone. With a specific app open? Points to an app conflict or resource drain. Restore: Erases all data and installs the latest compatible iOS firmware.

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