[SOLVED] I'm looking for KXD Blue Sea S25 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my KXD Blue Sea S25. 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.

@Lea

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 KXD Blue Sea S25 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/436535/Will+not+run+solenoid+clicks
Take a look at comment #198
Also, this : https://www.ifixit.com/Guide/MSI+GT62VR+6RD+Dominator+Hard+Drive+Replacement/115691.
You can also check this video starting from minute 9:

The KXD Blue Sea S25 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 KXD Blue Sea S25 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 KXD Blue Sea S25 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 KXD Blue Sea S25 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/asj2-official-stock-fw-update-ota-for-galaxy-note-10-5g-sm-n976b.3979897/

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

By methodically progressing through software checks, physical inspections, swap testing, and advanced motherboard diagnostics, you can accurately pinpoint the cause of smartphone display brightness faults.8. Heat: Apply heat to the edges of the screen or back cover (depending on the phone design) to soften the adhesive. There is no simple fix for this without specialized equipment or motherboard repair to "re-pair" a new sensor. Component Damage on Flex: Some small components (e.g., capacitors, resistors) might be located directly on the display flex cable. Micro Drill Bit and Pin Vice/Drill Press (Absolute Last Resort): For drilling out the screw head. Device Software Checks: Newer smartphones, especially iPhones, increasingly perform software checks on component serial numbers. While less common immediately after a speaker replacement, damage to the logic board cannot be entirely ruled out. Ensure the ambient light and proximity sensors align perfectly with their respective cutouts in the frame/display. This would require opening the phone for inspection, which is a job for a qualified technician. Stuck Button (Short Circuit): If the multimeter beeps and shows low resistance even when the button is not pressed, the switch is permanently closed (shorted), or there's a short on the flex cable itself. This can sometimes dislodge minor debris or "reset" a stuck physical contact. To test this, open a responsive app, like a game that requires quick taps, or simply navigate the UI rapidly. Use the built-in voice recorder app to record a short clip and play it back. Developers constantly release updates that include bug fixes, performance improvements, and compatibility enhancements. Locate Antenna Connectors: Cellular antennae often connect via small coaxial cables (thin black wires) with tiny snap-on connectors on the motherboard or a daughterboard. The repair process will require a clean, anti-static workspace, a precision screwdriver set, spudgers, opening picks, a heat gun (for adhesive), and a replacement fingerprint sensor module specific to your phone model. Beyond the main display seal, other smaller seals and gaskets also contribute to a phone's water resistance. Does it show any signs of discoloration, melting (from a short), or warping? Application: It's useful for quickly checking if two points are directly connected. Basic Tristar/Hydra diagnosis is a fundamental building block for advanced smartphone motherboard repair. New Adhesive Strips/Gaskets (Optional): If you need to re-seal the phone for water resistance. Pinching or Bending During Reassembly: When closing a device, if a flex cable is not routed correctly or is caught between two rigid components, it can be pinched or sharply creased, leading to internal damage or an immediate tear. No Signal/Connectivity: Points to RF transceivers, FEMs, or antenna connections. Common Combination 1 (Most Android Devices): Press and hold the Power button, then quickly press and release the Volume Up button. Camera Bracket/Housing: A plastic or metal frame specifically designed to hold all these components in their precise positions relative to each other and the display cutout. Intermittent Charging: The phone starts and stops charging randomly, often accompanied by repeated connection/disconnection sounds or notifications. If using liquid OCA glue: Apply an even, controlled amount of liquid glue to the center of the LCD. Clean Frame: Thoroughly clean any old adhesive residue from the phone's frame. Water damage can corrode the NFC antenna or its connections to the main logic board, or even damage the NFC chip itself. If the battery health is significantly degraded (e.g., below 80% capacity), it might be contributing to charging issues, especially slow charging.

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