[SOLVED] I'm looking for CHIVA V936 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my CHIVA V936. 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.

@Amel

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 CHIVA V936 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/804906/Can+I+turn+my+iMac+21.5%22+2015+into+an+external+monitor+for+PC
Take a look at comment #961
Also, this : https://www.ifixit.com/Answers/View/401104/Amplify+my+car+speakers.
You can also check this video starting from minute 2:

The CHIVA V936 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 CHIVA V936 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 CHIVA V936 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 CHIVA V936 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/lg-d295-boot-certification-verify-error-download-mode-doesnt-work.3705762/

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

Battery Issues: A severely degraded, damaged, or completely dead battery might not be able to accept a charge. Substrates: Insulating materials (like FR-4) separate the conductive layers. If all software and external checks fail, the problem likely lies within the phone's hardware. Presence of Power: If the phone was powered on when submerged, damage is usually much more severe due to immediate short-circuiting. Lower Screen Resolution/Refresh Rate: Some high-end phones offer QHD+ resolutions and high refresh rates (90Hz, 120Hz). Operating System Bugs: OS versions can have bugs affecting network stack stability. A stereo microscope (like an AmScope or similar) with good magnification (7x-45x) is essential for inspecting tiny pads, aligning chips, and observing solder reflow. After the adhesive has had sufficient time to cure (ideally 2-4 hours, or up to 24 hours for B7000 glue): In the world of smartphone repair, safely separating the display assembly from the main frame is often the very first and most critical step. Soldering Iron (fine tip), Flux, Solder Wire (0.3-0.5mm), Desoldering Braid: Only if the motherboard-side connector is damaged and requires micro-soldering. Diagnosing motherboard grounding issues requires patience, meticulous inspection, and a good understanding of circuit principles. If the sensors are on a separate flex cable (which sometimes happens for proximity, ambient light, and gyro/magnetometer), carefully inspect the flex cable for tears, kinks, or corrosion. Prolonged excessive heat can delaminate PCB pads or damage nearby components. The charge controller, often integrated into the Power Management IC (PMIC) of a smartphone, is a sophisticated component critical for managing battery charging, power distribution, and overall device power efficiency. Modern smartphones often integrate a Hall effect sensor to intelligently manage the screen's state in conjunction with magnetic flip covers. Manufacturer-Specific Calibration Tool/Jig: This is the most crucial component. In many phones (especially iPhones), the Taptic Engine is located at the bottom-right or bottom-left corner, near the charging port assembly. A slight bend can break the microscopic solder balls or create "cold solder joints" that are intermittently connected. If your device allows, drop the resolution to FHD+ and/or reduce the refresh rate to 60Hz when you prioritize battery life over visual fluidity. Apply a small amount of heat to the back of the phone where the battery sits (this helps soften the adhesive). Audio Issues (Mic/Speaker): Inspect the flex cables connecting the microphones/speakers. Similar to Android, some specific apps (e.g., WhatsApp) have their own in-app backup options, often integrating with iCloud Drive. This prevents any power from flowing through the device during the repair. If the phone becomes more stable after disabling Bluetooth, it suggests a conflict related to the Bluetooth hardware or its drivers. Vetting Tips: Check their industry reputation, read reviews from other repair technicians on forums, request sample orders, and thoroughly review their warranty and return policies. This can sometimes resolve software glitches that might be preventing the backlight from turning on. However, a successful repair can restore full battery life and cellular functionality to an otherwise "dead" or severely crippled smartphone, representing a significant accomplishment in electronics repair.8. Screws: Some bezels are screwed directly to the main chassis from the inside. Heat gun or hot plate (for devices with strong adhesive, especially screens) This can stem from a variety of sources, from simple external factors to intricate logic board component failures.

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