[SOLVED] I'm looking for Bq Aquaris M5.5 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Bq Aquaris M5.5. 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.

@Hoda

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 Bq Aquaris M5.5 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://xdaforums.com/t/q-google-play-advanced-search.2774713/
Take a look at comment #476
Also, this : https://xdaforums.com/t/need-help-my-status-bar-is-really-gone-not-anymore.1317826/.
You can also check this video starting from minute 7:

The Bq Aquaris M5.5 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 Bq Aquaris M5.5 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 Bq Aquaris M5.5 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 Bq Aquaris M5.5 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/457351/Boot+loop+on+iPhone+8+without+home+button

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

Visual Check: After reassembly, visually inspect all seams and openings for any gaps or misalignments. Combined Issues: Remember that Wi-Fi and Bluetooth issues often stem from the same shared IC. Always remember that patience and thoroughness are your best tools in this intricate repair.## 5. Use a desoldering iron with a wide tip or desoldering braid to remove all old solder, leaving flat, clean, shiny pads. Zoom in on the taken pictures to check for overall sharpness, detail, and absence of blurring. Rigid Containers: Hard plastic organizers, component trays with lids, or sturdy cardboard boxes provide protection against crushing. Water/Impact Damage: Look for signs of water ingress (green/blue corrosion, white residue) or physical impact (dents, cracked components) around the antenna connections and the general RF section of the motherboard. Positioning and Alignment: This is the most critical step for the proximity sensor. After the dwell time, remove the hot bar and immediately apply sustained pressure with a clamp or a weight over the bonded area while it cools completely. Many replacement displays are "bare" and require you to transfer several components from your old, broken display. Degraded Battery: While a degraded battery primarily means reduced capacity, making the phone's lifespan shorter, it can sometimes be perceived as faster "drain" because the reduced capacity runs out quicker. In such cases, the faulty IC (integrated circuit) would need to be desoldered using a hot air rework station, and a new IC precisely soldered in its place. This meticulous approach not only prevents costly mistakes but also ensures the longevity and reliable functionality of the repaired device.3. Color Discrepancy: For devices with a unibody design or where the screen's frame is integrated, look for slight discoloration or stress marks around the edges, suggesting pressure. Clean: Once cool, thoroughly clean the area with IPA and a brush to remove all flux residue. Does the power-off menu appear, or does it activate your voice assistant (depending on phone settings)? If you prefer not to remove it entirely, ensure you provide clear instructions or the passcode to the technician. Inaccurate Compass: Compass app points in the wrong direction or spins erratically. In most smartphones, the main microphone is integrated into the charging port flex cable assembly at the bottom of the phone. When cleaning, extreme caution is paramount to avoid damaging the delicate speaker components. If a function connected by a ribbon cable isn't working after a repair (e.g., no touch, no display, camera not detected), the first and most common troubleshooting step is always to re-open the device and carefully inspect and re-seat the relevant flex cable connector. Signal Integrity: Even minor damage can significantly degrade wireless signal strength. Inspect the corresponding contact pads on the logic board for corrosion or damage. Part of the Back Cover/Glass: On some older or specific models, the antenna section might be a distinct plastic piece within the back cover itself, or sometimes even part of a plastic "window" on a glass back. Power Management: Battery saver modes or aggressive power optimization settings can sometimes reduce the frequency or strength of haptic feedback, potentially contributing to a perception of delay or weakness. Physical Damage: A tiny piece of metal (e.g., a stray screw, metal shard, or a damaged component lead) bridging two traces. Even clear protectors can block IR light if not perfectly transparent in the sensor's area. If not, disconnect all its flex cables (main display, digitizer/touch, possibly earpiece or front camera if integrated). Integrated into Flex Cables: The motor is soldered directly onto a flex cable assembly that is then mounted. Use a thin plastic pry tool or playing card to carefully separate the back glass from the frame.

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