[SOLVED] I'm looking for FONERANGE Big Friendly 2 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my FONERANGE Big Friendly 2. 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.

@Dennis

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 FONERANGE Big Friendly 2 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-n9970-looping-on-android-logo-welcome-image.2438158/
Take a look at comment #1617
Also, this : https://xdaforums.com/t/overcharge.1768817/.
You can also check this video starting from minute 10:

The FONERANGE Big Friendly 2 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 FONERANGE Big Friendly 2 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 FONERANGE Big Friendly 2 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 FONERANGE Big Friendly 2 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/773435/Need+help+identifying+a+RUUD+condenser+dual-run+capacitor

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

Similarly, bent or damaged pins in the charger or computer ports can prevent proper engagement. If the modem is constantly searching for a signal, trying to re-establish a connection, or encountering errors, it will consume significantly more power. For users of VR headsets (like Google Cardboard or Samsung Gear VR) or AR applications, a malfunctioning gyroscope will manifest as significant drift, lag, or incorrect spatial orientation, making the virtual or augmented environment unstable and unusable. LRAs are much more precise, offering sharper, more localized, and more varied haptic effects. Phone Not Powering On: Ensure the battery is correctly inserted and charged. Use a flashlight to peer into the SIM slot , you might see a small white or silver sticker that will be red if wet. Diagnosing the root cause requires a methodical approach, starting with simple software checks and progressing to meticulous hardware inspection and, if necessary, component replacement. If a high current persists, the fuse will blow, opening the circuit completely. Caution: Excessive heat can damage surrounding components, melt plastics, or damage the battery. Extended Lifespan: Users can replace worn-out parts (like a failing camera or a charging port) rather than replacing the entire phone. Most operate by installing a client app on the smartphone and connecting it to a PC-based or cloud-based server. This process helps determine if the issue is with your phone, the cable, the charger, or the computer's ports/drivers. Identify Backlight Circuit: Use schematics or boardview to identify the backlight circuit components, specifically the backlight driver IC, the main backlight inductor (coil), and any associated diodes (e.g., a backlight diode). Spectrum Analyzer (Advanced/Specialized): The most direct way to detect EMI. Their ability to provide rapid, strong, and optically clear bonds has enabled highly complex repairs, particularly in the realm of screen refurbishment and micro-soldering. Coil whine is specifically characterized by its high frequency and often variable nature. All three gyro readings should be very close to zero (e.g., 0.00-0.05 rad/s). Identify the specific antenna(s) relevant to the problem (e.g., if it's a Wi-Fi issue, find the Wi-Fi antenna). How to Identify and Test Different Layers of a Laminated Smartphone Screen Physical impact from drops, severe vibrations, or liquid damage can physically damage this sensor, causing it to fail, become unresponsive, or report inaccurate data. Repairing a broken screen latch mechanism is crucial for the longevity and safety of your smartphone. Remove the case and re-evaluate the temperature during demanding tasks. Battery drain will also be significantly accelerated, as the components work harder and less efficiently at higher temperatures. You might notice your phone no longer holding a charge as long as it used to, unexpected shutdowns even with a seemingly adequate charge, excessive heating during use or charging, or even the battery physically swelling. Inspect: Under high magnification, visually inspect the solder joints. This constant power draw can also cause the area around the audio IC to become noticeably warm to the touch. Clean the surface of the display to remove any loose glass shards, dust, or grease. Hold the driver perfectly still, with firm downward pressure, for 30-60 seconds, allowing the glue to bond. The good news is that troubleshooting a non-vibrating phone often starts with simple software checks before delving into hardware. Spreading (Optional): In smartphone applications, the pressure from reassembling the cooling element usually spreads the paste sufficiently.

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