[SOLVED] I'm looking for MOBIISTAR E1 Selfie repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my MOBIISTAR E1 Selfie. 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.

@Norbert

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 MOBIISTAR E1 Selfie 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/276550/Why+does+my+air+conditioner+only+work+sometimes+(intermittently)
Take a look at comment #879
Also, this : https://www.ifixit.com/Answers/View/325556/Bad+connection(Is+my+attena+broken).
You can also check this video starting from minute 3:

The MOBIISTAR E1 Selfie 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 MOBIISTAR E1 Selfie 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 MOBIISTAR E1 Selfie 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 MOBIISTAR E1 Selfie 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/q-well-i-did-everything-the-way-you-guys-said-but-i-have-grey-screen-now.1069381/

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

Software Update/Factory Reset: Ensure your operating system is up to date. Transparency: The customer must be fully informed about what they are getting, what the process entails, and all potential consequences. Remove Shields/Brackets: Identify any small metal shields or brackets covering the display and digitizer flex cable connectors. These can be scratched or severed during prying, leading to signal loss and low volume. Disconnect: Use a plastic spudger to gently pry the battery flex cable connector straight up from its socket on the motherboard. Complete Removal of Old Display: Fully disconnect all flex cables associated with the old display assembly (main display, digitizer/touch, sometimes front camera/earpiece). Applying a screen protector to a smartphone can often feel like a delicate surgical procedure, fraught with the potential for annoying air bubbles, frustrating dust specks, and misalignment. Other brands: Often use custom tools or generic Fastboot flashing scripts. This prevents accidental short circuits and protects the device's sensitive electronics from power surges or static discharge during component manipulation. Look for `OL` (open line), which could indicate a broken trace to the antenna or a faulty component, or 0mV (short to ground). Disconnect Battery: Always the first step to prevent shorts and power to the board. This requires keen observation and often magnification (jeweler's loupe 10x-30x, or a USB microscope). Board-Level Issues: In rare and advanced cases, the issue might stem from a damaged component on the logic board itself that supports the fingerprint sensor (e.g., a faulty IC or a broken trace). In other cases, a small piece of copper foil or a tiny part of a donor board pad can be carefully shaped and adhered, then connected via jumper wire. Systematically uninstall recently installed or suspicious apps to identify the problem. The phone will consistently display a "No SIM card detected," "SIM error," or "Insert SIM card" message, even when a working SIM card is properly inserted. Diagnosing and locating a short on this intricate board is one of the most challenging yet rewarding aspects of advanced smartphone repair. Fixing an "invalid battery" message can be a nuanced repair, but by following a systematic diagnostic and repair process, you can effectively pinpoint and resolve the underlying issue. Basic Functionality: The screen powers on, displays an image, and has some basic touch response. Modern smartphones typically use a 3.5mm TRRS (Tip-Ring-Ring-Sleeve) jack, which supports stereo audio output and a microphone input. While not its primary purpose, a large ground plane also helps dissipate heat generated by ICs. Infrared Emitter (Flood Illuminator): This component emits a flood of invisible infrared light. If your phone feels uncomfortably hot to hold, or if you can't keep your hand on the device for more than a few seconds, it's definitely a sign of overheating. Caveats: This method is highly controversial and often cited as damaging to the oleophobic coating. The choice of soldering alloy is critical, influencing everything from manufacturing efficiency and device reliability to environmental impact and repair feasibility. A multimeter can be used to perform continuity checks and confirm that there are no shorts on the power lines to the IC. Inspect: Under high magnification, visually inspect the solder joints. Logic Board Connector Check: Carefully inspect the FPC connector on the logic board under a microscope. Liquid Damage: While often causing direct shorts or corrosion, liquid can also seep between layers, weakening the adhesive and leading to delamination over time, especially if combined with thermal cycling. Dirt and Debris: Accumulation of dust, lint, or other debris on contact points can create an insulating layer, breaking the ground connection.

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