[SOLVED] I'm looking for ARROWS FCG01 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my ARROWS FCG01. 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.

@Axel

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 ARROWS FCG01 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/534677/Can+you+tell+which+of+these+two+cheap+2.1+amp+board+is+better
Take a look at comment #465
Also, this : https://www.ifixit.com/Wiki/Samsung_Galaxy_J7_Troubleshooting.
You can also check this video starting from minute 6:

The ARROWS FCG01 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 ARROWS FCG01 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 ARROWS FCG01 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 ARROWS FCG01 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/351841/The+speakers+on+my+laptop+aren't+working

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

Replacement foam/rubber material (if exact mounts aren't available, small pieces of high-density foam or soft rubber can be improvised). Contact Customer Service: If you can't find the information online, call your carrier's technical support or visit a retail store. Place it in a fire-resistant container (e.g., a bucket of sand) or outdoors immediately. Avoid direct, prolonged heat on any single spot or the flex surrounding the IC. The NFC system in a smartphone typically consists of two main parts: the NFC chip, which processes the data (often integrated into the PMIC or a separate dedicated IC on the logic board), and the NFC antenna. Check for proper voltage output from the baseband PMIC (if functional) when the board is powered on. Avoid excessively vigorous shaking if a rattle is confirmed, as it could worsen the problem. In-Circuit Measurement (Caution): Measuring resistance of capacitors in-circuit can be misleading due to parallel paths. This mode is a direct interface to the device's internal memory (eMMC or UFS) and is used by service centers or advanced users to flash official firmware, especially after a failed update, a bad custom ROM flash, or severe software corruption that prevents the device from booting normally or even reaching fastboot/recovery modes. Directive 2002/58/EC on privacy and electronic communications, alongside national criminal codes, forms the basis for prosecuting such activities. IC Replacement: If the baseband IC is confirmed to be faulty, replacing it is the only option. Apply a tiny, tiny drop of super glue or slow-drying epoxy to the tip of the correct size screwdriver bit. Turn your phone off completely, wait for 30 seconds, and then turn it back on. The most common hardware fixes involve reseating or replacing the camera module or its flex cable, making this a manageable repair for those comfortable with smartphone disassembly.8. If this is missing or damaged after a screen replacement, the sensor will malfunction. The initial interaction with the customer and the device sets the stage for the entire repair process, and accurate documentation here is paramount. Check display quality, colors, and test transferred components like the front camera and earpiece. Anti-Static Mat and Wrist Strap: To prevent electrostatic discharge (ESD) damage. Download `boot.img`: Obtain the correct `boot.img` file for your device and firmware. Disconnect the battery flex cable immediately after opening the phone to prevent any accidental shorts. Visual Inspection: Eject the SIM tray and inspect the internal slot with a flashlight for dust, lint, or bent internal pins. Masking Complexity: Imperfect masking can lead to non-functional connectors, poor thermal performance, or blocked sensors. Observe if light from the phone's backlight or an external light source (shone through the gap from the side) is visible through the crack. In severe cases, pins can be completely broken off or pushed down into the connector housing. Once the entire strip is accurately positioned, firmly press it down along its entire length to activate the adhesive and ensure it adheres securely to the frame. If True Tone isn't critical to you, it might be acceptable to live without it. Other functions not working: If something else isn't working (e.g., camera, Wi-Fi, haptics), it's highly likely that another flex cable was either damaged or not properly reconnected during the process. Corrupted Firmware/Software Bugs: The software responsible for reading and interpreting sensor data can become corrupted, leading to incorrect readings or actions. Note its package size (e.g., 0402, 0603) for sourcing the replacement. USB Cable: A high-quality, reliable USB cable is essential for a stable connection.

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