[SOLVED] I'm looking for Qmobile Noir E8 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Qmobile Noir E8. 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.

@Nicole

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 Qmobile Noir E8 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/Lenovo+IdeaPad+Flex+5-1570+Back+Panel+Replacement/130824
Take a look at comment #1370
Also, this : https://www.ifixit.com/Answers/View/600235/Dropped+MBP,+is+the+display+repairable.
You can also check this video starting from minute 9:

The Qmobile Noir E8 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 Qmobile Noir E8 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 Qmobile Noir E8 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 Qmobile Noir E8 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/694285/I+would+like+to+replace+my+battery.+Which+battery+do+I+need.

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

By following these steps and using the right tools, you can successfully identify and rectify even the most stubborn shorts on a smartphone logic board.3. Ensure "Auto-Rotate" is enabled in your quick settings or display settings. Set the voltage to the phone's battery voltage (e.g., 3.8-4.2V) and limit the current (e.g., 1-2A). Charging Issues: Rare, but severe EMI could theoretically disrupt charging IC communication. While not strictly an intermittent charging issue, it often accompanies them. Putting a long screw into a hole meant for a short one can pierce the logic board and destroy your phone (a common mistake called "long screw damage"). Verify that all internal screws are replaced in their precise, original locations; using a screw of incorrect length or type in the wrong hole can cause serious "long screw damage" to the underlying logic board. In today's interconnected world, reliable wireless data is paramount, and any instability severely impacts user experience, productivity, and communication. Iron Temperature: Use the lowest effective temperature to prevent damaging fine traces or lifting pads. Clean and Re-seat: Before reassembly, ensure all contacts are clean and free of debris. Once the solder is molten, give the chip a very gentle nudge with tweezers to confirm it's floating on the solder. It typically results from moisture exposure, but can also be exacerbated by prolonged exposure to high humidity, or in rare cases, electrical arcing. Component Proximity: Directly beneath the shield and often very close to its edges are highly sensitive ICs, passive components, and flex cable connectors. For resistors or capacitors, the schematic provides their values (e.g., 10kΩ, 100nF), ensuring the correct replacement part is used. Diagnosing and repairing it requires a systematic approach, starting with simple software checks and progressing to intricate board-level diagnostics and micro-soldering techniques. These flex cables are often adhered to the phone's frame, so gentle heat (from a heat gun) is required to soften the adhesive before carefully peeling it away. This insulates the wire and secures it, preventing it from breaking or shorting. Security Risks: An unlocked bootloader makes the device more vulnerable to malicious software. Internal Layers: Sandwiched between the outer layers are internal signal layers and power/ground planes. iOS: Go to `Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings`. Monitor Current Draw: The DC power supply will display the real-time current draw. Liquid Damage: Using incorrect cleaning solutions or excessive liquid can lead to corrosion. These connectors are very small and delicate; excessive force or twisting can damage the connector on the mainboard or antenna module, which is a much more difficult and costly repair. Check for any dust particles under the lens by taking photos of a bright, uniform surface. Apply a thin, even layer of liquid flux to the clean pads on the motherboard. Apply gentle, even heat (around the edges) with a heat gun/hair dryer for 30-60 seconds. However, their effectiveness can be limited by iOS updates, the specific type of damage, and the quality of the replacement part. Once all balls have formed, turn off the hot air and allow the chip to cool naturally. Static electricity can damage the battery's protection circuit board (PCB), leading to malfunction. ZIF (Zero Insertion Force) Connector: The flex cable typically connects to the logic board via a snap-on ZIF connector.

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