[SOLVED] I'm looking for NUU A11L repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my NUU A11L. 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.

@Carlo

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 NUU A11L 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/740125/Screen+is+completely+removed...can+I+access+anything+when+plugged+in
Take a look at comment #510
Also, this : https://www.ifixit.com/Answers/View/922201/Screen+freeze-goes+back-color+bars+after+installing+new+display.
You can also check this video starting from minute 8:

The NUU A11L 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 NUU A11L 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 NUU A11L 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 NUU A11L 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/Wiki/Amazon_Kindle_8th_Gen_Not_Charging

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

Use a flashlight and a non-conductive tool (e.g., plastic toothpick) to gently clean the port. Security Type: Try temporarily changing the Wi-Fi security type (e.g., from WPA3 to WPA2/AES) on your router to check for compatibility issues, especially with older phones. If a battery is swollen, handle it with extreme care and dispose of it properly. Examine the entire length of the cable and both connectors meticulously. In the intricate world of smartphone logic board repair, few concepts are as fundamental and yet as often overlooked as grounding continuity. When a smartphone board has been subjected to liquid, even after meticulous cleaning and component replacement, residual vulnerabilities can remain. Lithium-ion Battery: The most common source of thermal runaway due to internal short circuits, overcharging, or physical damage. If your phone's screen is pushing out, the back cover is bulging, or there's a visible gap in the seams, it's highly likely the battery is swelling. Wear and tear: Repeated pressing over time can cause fatigue in the flex material. Any strange characters, missing entries, or generic "unknown" values can be suspicious. If any internal components (like the earpiece, front camera, or home button assembly) are still attached to the broken screen or obstruct the frame edges, carefully transfer them to the new screen or temporarily remove them from the frame if they impede glass removal. This process is called "reballing," and it's where soldering stencils and paste become crucial. A heat gun is often used to get the initial opening gap, then one of these plates for full separation. Plastic Spudger/Prying Tools: To safely open the phone and disconnect components. On the board, they might be tiny black or white rectangular components. Power Management and Efficiency: With displays being one of the most power-hungry components of a smartphone, the DDI also incorporates sophisticated power management algorithms. Faulty Component on Rail: The component (e.g., CPU, RAM) that the LDO is powering might be shorted internally, causing the LDO to fail or shut down. After the shield has cooled, clean the entire area thoroughly with isopropyl alcohol and a soft brush to remove all flux residue. Common challenges when working with schematics include the sheer volume of information, the abstract nature of the diagrams, and occasionally poor quality or incomplete schematics. Symptoms: Most noticeable at low brightness settings, often in dimly lit rooms. Identification: Often brown, beige, or sometimes gray rectangular chips. Check for the presence and stability of these voltages with the charger connected. Retrieve SIM/MicroSD Cards: Carefully remove your SIM card(s) and/or microSD card from the tray. Navigate to the directory where your OTA update `.zip` file is stored. EIS (Electronic Image Stabilization) Glitch: EIS relies on software to crop and shift the image. Do not insert tools too deeply into the device, as this can sever flex cables or damage internal components. Z3X Box (Samsung Tool PRO): Specifically for Samsung devices, offering extensive repair features including direct unlock, firmware flash, EFS repair. Wi-Fi Channel Overlap: Neighboring Wi-Fi networks using the same channel. Using excessive heat during smartphone disassembly is a critical mistake that can lead to irreversible damage, increasing repair costs, extending repair times, and potentially compromising the safety and functionality of the device. If the hinge components themselves are worn or corroded, a deeper intervention is required.

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