[SOLVED] I'm looking for Hisense Infinty KO C20 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Hisense Infinty KO C20. 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.

@Valerio

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 Hisense Infinty KO C20 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/please-help-boot-loop.694675/
Take a look at comment #704
Also, this : https://www.ifixit.com/Answers/View/409020/cannot+unscrew+2.2mm+screw+for+iPhone6.
You can also check this video starting from minute 8:

The Hisense Infinty KO C20 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 Hisense Infinty KO C20 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 Hisense Infinty KO C20 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 Hisense Infinty KO C20 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/Guide/Acer+Iconia+W3-810++Screen+Replacement/71525

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

ADB (Android Debug Bridge) & Fastboot: Command-line tools that facilitate communication between a computer and an Android device, essential for flashing and debugging. Most operate by installing a client app on the smartphone and connecting it to a PC-based or cloud-based server. Ensure all pins/pads are perfectly aligned with the pads on the board. Pre-tin New Connector: If the new connector comes without solder on its pins, apply a small amount of flux and carefully pre-tin each pin using your fine-tip soldering iron and fine solder. This is almost guaranteed to remove all software-based malware, but it will also erase all your personal data, apps, and settings. Some cases are designed to be NFC-compatible, but it's worth checking. This is not a task for the faint of heart or the inexperienced hobbyist; it demands precision, patience, specialized tools, and a steady hand. Check for shorts between antenna traces and ground, or between adjacent traces. Analyzing smartphone charging temperature spikes is crucial because excessive heat during charging can degrade battery health, damage internal components, and, in extreme cases, pose a safety risk. Use: Place the bent frame into the jig and carefully adjust the screws or clamps to apply corrective pressure. Is it flush with the frame, or does it appear recessed, unusually protruded, or tilted? Are there any visible cracks or damage to the button cap? There should be no continuity (no beep/OL reading) between adjacent power/data pins. The impact and consequences of pressure marks are primarily aesthetic, detracting from the visual quality of the screen. Logic board replacement is typically considered in the following scenarios: Liquid Damage: Water or other liquids can cause corrosion on the display connector pins, the display flex cable, or the display driver IC on the logic board. Type of screw head: Phillips, Torx, Pentalobe, Tri-wing? This helps in choosing tools. While some solutions require patience and careful execution, restoring your phone to a state where it can freely download updates and install new applications is a rewarding endeavor that significantly enhances your smartphone experience. SIM Tray: The physical carrier that holds the SIM card and inserts into the device. Damaged Traces: Microscopic traces leading to/from the IC can be broken. High heat can melt or permanently damage this adhesive, leading to bubbles, dead spots, or complete delamination, making the screen unusable. Repairing Damaged Trace Lines (Jumpers) on a Multi-Layer Smartphone PCB Before embarking on this repair, it's essential to understand the specific antenna configuration of your smartphone model. Physical Damage Inspection: Visually inspect the phone for any signs of physical damage, especially near the top or edges where Wi-Fi antennas are often located. Bending or deforming a Li-ion battery can also damage its internal structure, leading to swelling or internal short circuits over time. The key is to be aware of the subtle differences in price, packaging, branding, and physical characteristics. If your phone struggles to discover networks, repeatedly disconnects, or exhibits very slow Wi-Fi/Bluetooth performance, it's worth considering the modem, although these often have their own dedicated firmware. The camera stabilizer module, specifically referring to the Optical Image Stabilization (OIS) mechanism, is a sophisticated piece of engineering designed to counteract handshakes and vibrations during photo and video capture. The adhesive needs time and sustained pressure to fully cure and form a strong, lasting bond. Cons: Doesn't visually represent the exact original placement within a component, so you still need to remember which screw goes where within that group. SD Card Formatter Tool: For stubborn cards, consider using the official SD Card Formatter tool from the SD Association.

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