[SOLVED] I'm looking for NINETOLOGY U9 P2 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my NINETOLOGY U9 P2. 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.

@Djamel

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 NINETOLOGY U9 P2 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/mystery-edge-clock.3096812/
Take a look at comment #818
Also, this : https://www.ifixit.com/Guide/Nokia+Lumia+928+Back+Cover+Replacement/61638.
You can also check this video starting from minute 1:

The NINETOLOGY U9 P2 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 NINETOLOGY U9 P2 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 NINETOLOGY U9 P2 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 NINETOLOGY U9 P2 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/339183/How+to+remove+Oil+marks+from+display

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

For hairline cracks: If possible, apply a very thin layer of super glue (cyanoacrylate) from the inside of the back panel to bind the crack. You'll then need to identify and uninstall recently installed or suspicious apps. Look for bends, cracks, tears, or signs of corrosion (green/white deposits). Disassembly: Follow a reliable guide for your specific phone model (e.g., from iFixit). Safe Mode starts your phone with only essential system apps, disabling all third-party applications. Place the positive probe on the positive terminal of the battery connector on the motherboard and the negative probe on a known ground point (e.g., a screw hole or metal shield). Carefully and evenly apply a continuous, thin bead of B-7000 (or equivalent) adhesive around the entire perimeter of the smartphone frame's bonding surface. If re-seating and cleaning do not resolve the issue, the problem likely lies with more severe damage to the flex cable or the FPC connector itself. DeoxIT products are designed to leave a protective film, so a full "dry" might not mean zero residue, but rather the solvent carrier evaporating. Erratic Touch: Touch input is inconsistent, laggy, or registers inaccurately. Clean Workspace: Work in a well-lit, clean, and organized area to prevent losing tiny screws or dropping components. Inspect Frame and Bezel: Thoroughly inspect the phone's metal or plastic frame and the bezel of the screen/back cover for any bends, dents, nicks, or burrs. Check for any signs of pitting or erosion, especially if there has been liquid damage. Restart Phone: A simple reboot is often effective in clearing temporary software glitches affecting sensor readings. Frequent deletion and installation of apps, as well as large media transfers, exacerbate this. Pedometer inaccuracy: Step counter apps show inconsistent or incorrect step counts. Liquid Damage/Corrosion: The baseband IC and surrounding components are vulnerable to liquid damage. Identify the metal shields covering the logic board connectors, particularly those related to the rear camera module. For cosmetic repair, you might need super glue (cyanoacrylate), plastic filler or epoxy, very fine-grit sandpaper (e.g., 400-2000 grit), plastic primer, and spray paint matched to your phone's color (optional, for a re-finish). Waterproofing: If your phone was water-resistant and you removed the screen or rear panel, ensure you clean off all old adhesive residue and apply a new waterproofing adhesive gasket to restore its seal. For modern Lithium-ion batteries, there's no "memory effect" in the traditional sense, so deep discharge/recharge cycles are generally not needed for calibration. Monitor Charging Current (Apps): Use apps like AccuBattery, Ampere, or CPU-Z (for Android) to monitor the actual charging current (in mA). Slow Speeds: Even if a connection is maintained with seemingly adequate signal bars, data transfer speeds might be significantly slower than expected. Once booted, go to your settings and check for Wi-Fi and Bluetooth functionality. Host Phone Overheating: The smartphone acting as the hotspot becomes excessively warm, which can lead to performance throttling and connection drops. Use: Always store spare motherboards, flex cables, and ICs in proper ESD bags. Damaging Flex Cables: Be extremely gentle when disconnecting and reconnecting. Work in small sections, ensuring the gasket is perfectly aligned with the frame's edge and sits flat without any bubbles, creases, or overlaps. Smartphones, despite their advanced hardware, often encounter software glitches that can range from minor annoyances to critical failures, rendering the device almost unusable. If the issues persist here, it points away from third-party apps and towards a core OS or firmware problem.

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