[SOLVED] I'm looking for KRONO Net Max Go repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my KRONO Net Max Go. 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.

@Denis

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 KRONO Net Max Go 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/galaxy-s-iii-galaxy-note-and-galaxy-note-10-1-added-to-ongoing-patent-lawsuit.1864424/
Take a look at comment #228
Also, this : https://xdaforums.com/t/problem-with-upgrade-qtek-a9100.493537/.
You can also check this video starting from minute 8:

The KRONO Net Max Go 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 KRONO Net Max Go 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 KRONO Net Max Go 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 KRONO Net Max Go 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/critical-low-memory.292434/

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

Solder Remaining Pads (Hot Air Method): Apply even heat from your hot air station to the new microphone. Dust/Debris: While usually harmless, excessive conductive dust can sometimes bridge connections. Low Dropout Regulators (LDOs): These are linear regulators that provide very clean and stable voltage output but are less efficient than buck/boost converters, as they dissipate excess voltage as heat. BGA (Ball Grid Array) chips are especially vulnerable to cracked solder balls under impact. Status Bar Icons: Battery indicators, Wi-Fi symbols, network bars, and clock displays often remain static at the top of the screen. The microscope is indispensable for visual inspection and precise component manipulation, while schematics provide the roadmap to the board's complex circuitry. Fuses are commonly found in power delivery paths, such as the main battery input, charging circuits, backlight circuits, and sometimes specific peripheral power lines. Respect privacy and legal boundaries regarding unlocking, IMEI repair, etc. In essence, every function within a smartphone, from the brightest pixel on the screen to the most complex calculation by the CPU, depends on a stable and correctly regulated power supply. Inspect the pads under the microscope for any damage, such as lifted traces or missing pads. For stubborn lint, a plastic toothpick can be used with extreme caution. Accessory Detection Issues: OTG devices (e.g., USB drives, keyboards) are not recognized. A heat gun is an indispensable tool in overcoming this challenge, allowing technicians to soften these strong adhesives, making components like back covers, displays, and batteries easier to remove without causing damage. Known Good Flex Cable: If the display has a separate, easily replaceable flex cable, try a new one. Check for Carrier Outages: Confirm with your carrier if there are any network outages in your area. Replacing this delicate surface-mount device (SMD) component is an advanced micro-soldering repair that requires specialized tools and a high degree of precision. Some adhesives may benefit from a small amount of gentle heat during this process, but verify compatibility with the gasket and device. Performance Throttling: The device experiences noticeable slowdowns, lag, or dropped frame rates in games and demanding applications, especially after extended use, as the system tries to cool down the processor. It's a specialized integrated circuit that acts as a boost converter, taking the lower battery voltage (e.g., 3.7-4.2V) and "boosting" it to a much higher voltage (e.g., 15-30V) required by the LED array. IMEI Repair/Write (Specialized Tools): For certain older devices and chipsets, specialized professional tools (e.g., Chimera Tool, Z3X Box, Octoplus Box, Hydra Tool) may have functions to "repair" or "write" a valid IMEI. Using your fine-tip tweezers, carefully pick up the new pressure sensor. Network Settings Reset: This clears all saved Wi-Fi networks, Bluetooth pairings, and cellular settings. Flex Cable Damage: Inspect the entire flex cable assembly for any tears, creases, nicks, or signs of liquid damage/corrosion. Scenario 2: Reworking Gold-Plated Pads (after component removal - most common in smartphone repair) Understanding why this occurs, despite appearances, is the first step towards a comprehensive resolution. Optimize Background: Change your phone's background to a plain, uniform color. Clean Old Adhesive: Scrape off any old adhesive residue from the frame and back cover using a plastic spudger and IPA. This involves sending low-level commands to the SE, instructing it to erase its current firmware and write the new image. Patience and a systematic approach are key to successfully addressing this issue. This effectively "clones" the cryptographic link, allowing the new sensor to function identically to the original.

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