[SOLVED] I'm looking for KUPA V10 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my KUPA V10. 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.

@Dominika

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 KUPA V10 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/port-please.2585019/
Take a look at comment #1651
Also, this : https://www.ifixit.com/Answers/View/801287/My+battery+light+came+on+in+the+dash+and+would+blink+on+and+off+I+have.
You can also check this video starting from minute 2:

The KUPA V10 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 KUPA V10 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 KUPA V10 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 KUPA V10 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/346081/My+computer+does+not+boot+the+system

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

Most capacitors should not show a short to ground on both sides unless they are intentionally grounded. More advanced DDIs also play a role in color management, mapping color spaces to ensure accurate reproduction of content. Apply Kapton tape precisely, ensuring it adheres well to prevent the coating from seeping underneath. Before considering hardware intervention, it's crucial to exhaust all software-related troubleshooting steps. This guide will walk you through a comprehensive assessment process, from initial visual inspection to detailed internal examination. Reattach the back cover, pressing firmly around the edges until all clips snap into place. Continue heating for a few more seconds to ensure all solder balls have reflowed properly. Look for excessive switching noise on VCC_MAIN or other primary rails. The Proper Technique for Soldering Gold-Plated Pads on a Smartphone PCB Software Artifacts: The logging application itself, OS background processes, or even the sensor driver's internal filtering can affect raw data. Toggle Airplane Mode: Turn on Airplane Mode for a few seconds, then turn it off. Play audio through the external speakers, make a phone call to check the earpiece and speakerphone, and record a voice memo to ensure the microphone functions correctly, indicating that all audio pathways are now clear. While software troubleshooting should always be the starting point, the ultimate solution often lies in the delicate art of microsoldering on the iPhone's logic board.9. Motherboard Controller Failure: A rare but possible failure of the SD card controller chip on the phone's motherboard. This common issue can manifest in several ways: the button might feel "mushy," not click satisfyingly, protrude unevenly, or move excessively within its housing cutout. If a force restart doesn't work, consider whether the display itself is faulty. Battery Disconnection: Always disconnect the battery immediately after opening the device to prevent short circuits. If the COF flex or IC is damaged, the entire display assembly typically needs to be replaced. Go to your sound settings and test the vibration (e.g., by enabling vibration for touch feedback, or triggering a test notification). Muffled audio, distorted sound, low call volume, unreliable charging, or even complete failure to charge are common symptoms of clogged ports and grilles. This reduces the contact area and can lead to intermittent connections. Gaming: Play a demanding 3D game for an extended period (15-30 minutes). If the problem persists after exhausting all software remedies, or if there are clear physical signs, the issue is almost certainly hardware-related, warranting professional attention.8. Backup Data: Before starting any major repair, it's wise to back up all important data on the phone. While standard lead-free solders (e.g., Sn/Ag/Cu alloys) are common, their high tin content makes them susceptible to gold embrittlement. Disconnect Battery FIRST: After opening the device, immediately disconnect the battery to prevent short circuits. A thermal camera, or infrared camera, detects infrared energy emitted by objects and converts it into a visible thermal image. Identify the Suspect Area: If there's no power, the issue likely lies within the power management system. Reflow/Reball Critical ICs: Sometimes, liquid damage causes bad solder connections on BGA chips like the PMIC or CPU. As a last resort for software troubleshooting, a factory reset (after backing up data) can rule out any deep software corruption.

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