[SOLVED] I'm looking for STRIKE A14 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my STRIKE A14. 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.

@Charlotte

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 STRIKE A14 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/LG+Fortune+Battery+Replacement/123404
Take a look at comment #1348
Also, this : https://www.ifixit.com/Answers/View/627358/Why+does+my+phone+not+finish+Extracting+Software+on+iTunes.
You can also check this video starting from minute 5:

The STRIKE A14 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 STRIKE A14 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 STRIKE A14 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 STRIKE A14 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/htc-music.1542912/

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

Apply light, even pressure until you hear or feel a soft click, indicating it has properly snapped into place. Constant plugging and unplugging of the charging cable, especially when done without care or by pulling on the cable rather than the connector, can bend or break the internal pins, loosen the connector's housing, or stress the solder joints. Water Resistance: While you can replace the glass, fully restoring the factory-level water resistance is extremely difficult for a DIY repairer. Patience: This is a meticulous job requiring patience and a steady hand. Blurry images / No focus: Ensure the camera module is seated correctly and not loose. Physical impact from drops, or liquid damage (especially if water enters its pressure port), can damage the sensor, rendering it inoperative or inaccurate. Drag Soldering: Excellent for drag soldering ICs, often preferred over chisel by some technicians due to its ergonomic angle. Checking Flex Cables: To verify a flex cable isn't torn internally, place probes on corresponding points at each end of a specific trace. Foreign Debris: Carefully look inside the phone for any tiny dropped screws, pieces of plastic, or other debris that might have been left behind. Actual Capacity: Compare the battery's original design capacity (e.g., 3000mAh) to its current actual capacity. Avoid harsh industrial solvents or household cleaners, which can damage delicate solder masks, plastics, or component markings. Apply a small amount of liquid flux around the edges of the Audio Codec IC. For internal inspections, ensure you are in an Electrostatic Discharge (ESD) safe environment, using an ESD mat and wrist strap, and utilizing appropriate non-conductive opening tools to prevent further damage. If the phone detects it's too hot (e.g., due to heavy usage while charging, direct sunlight, or a faulty component generating heat) or too cold, it will pause charging to prevent damage. Prerequisites: ADB & Fastboot tools installed on PC, correct factory image firmware, phone in Fastboot Mode. Disconnect Battery: As soon as you gain internal access, disconnect the battery. Low/Stable mA (e.g., 20-100mA after power button): Indicates the PMIC is trying to boot but is stuck. Gradually and incrementally apply pressure in the opposite direction of the bend. Remove Old Solder Mask: If the pad is gone and you need to expose the underlying trace, use a precision scalpel or fiberglass pen to very carefully scrape away the solder mask from the trace, exposing a clean copper surface. Inspect the Damage: Under the microscope, thoroughly inspect the broken USB-C port. Too Little Flux: Solder won't flow, resulting in cold joints or poor adhesion. Disconnect Battery: Disconnect the old battery's flex cable from the motherboard. Wrong Model/Variant: Using firmware designed for a different phone model, regional variant (e.g., SM-G998B vs. Be aware of flex cables often located on the sides or top; avoid inserting tools too deeply. Reset Network Settings: On both Android and iOS, there's an option to "Reset Network Settings." This clears all Wi-Fi, Bluetooth, and cellular settings (including VPNs and APN settings) and often resolves underlying configuration issues. Try codecs known for lower latency like aptX Low Latency (if supported by both phone and headphones). Disassembly is often required to inspect the Wi-Fi antenna and its connectors. With continuous, even hot air application, gently lift the can straight up off the board. A stable workbench, good lighting (preferably diffused, shadow-free), and a clean, contrasting background (e.g., white or black paper) are also crucial for achieving clear, professional-grade images. Unfortunately, internal storage chips are typically soldered directly to the motherboard, making replacement a complex and expensive procedure, often requiring specialized equipment and skills.

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