[SOLVED] I'm looking for Zte Grand X IN repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Zte Grand X IN. 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.

@Marlon

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 Zte Grand X IN 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/679306/I+just+installed+HDMI+cables,+and+now+I+have+no+audio.
Take a look at comment #1085
Also, this : https://www.ifixit.com/Answers/View/356425/soda+++3rd+gen+iPod+=+touch+screen+not+working:(((.
You can also check this video starting from minute 6:

The Zte Grand X IN 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 Zte Grand X IN 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 Zte Grand X IN 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 Zte Grand X IN 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/775458/GPU+Still+not+working+after+buying+new+one+for+iMac

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

Carefully disconnect the camera flex cable(s) with a plastic spudger and gently lift the camera out. Replacing a tactile feedback spring or the entire button flex cable is a delicate repair that requires patience and a steady hand. It’s not uncommon for a first attempt at micro-soldering to require a second pass. Burnt Components: Look for components that appear charred, discolored, or have small craters. Overload: Too much current is being drawn by a component, even if it's not a dead short. Remove Any Obstructing Components: Unscrew and carefully remove any brackets, flex cables, or other components that prevent clear access to the speaker unit and its mesh. Comparison with a Known Good Device: If possible, compare the haptic response of the problematic phone side-by-side with a known-good device (ideally the same model) using the same tests. Diode Mode Readings (using Multimeter & Schematic): This is a powerful, non-invasive diagnostic technique. Heat: Direct hot air again over the new capacitor and pads, using the same temperature and airflow settings as removal. However, many modern phones use pressure contacts where the springs are part of a replaceable module. Swollen Batteries: If a battery is visibly swollen (bulging or puffed up), it is extremely dangerous and must be handled with utmost caution. If the input voltage is missing, the problem lies further back in the power management. Multiple Components/Section Rework: If an entire section of the board with several components requires reflowing (e.g., after significant liquid damage affecting multiple ICs), a reflow oven can achieve this more effectively than a hot air station. With patience, the right tools, and careful attention to detail, it’s a manageable DIY fix for many smartphone users. Supplier Relationship Management: Build strong relationships with a few trusted suppliers. The PCB is the brain of the smartphone, housing all the critical components, integrated circuits (ICs), and intricate conductive traces that allow the device to function. Certifications: Ask suppliers for certifications or documentation proving the authenticity and quality of their parts. Reconnect any flex cables you detached, ensuring they are all firmly seated. Visual Damage: Look for signs of liquid damage, corrosion around its pins/balls, or physical damage (cracks, bulges). Instead, try to carefully pry without heat, focusing on the least swollen areas. Understanding the nuances between minor bleed, severe bleed, and normal display characteristics like IPS glow empowers you to make informed decisions about your device.## 2. These might include "No Service" errors, baseband issues, or IMEI corruption. Reconnect to Motherboard: If the motherboard was removed, replace it into the phone frame first. Liquid damage is another major culprit, as moisture can lead to corrosion on the contact points, impeding electrical flow. Transfer Components (if applicable): Many display assemblies come "bare" (without components like the front camera, earpiece speaker, ambient/proximity sensors, home button/fingerprint sensor, vibrator). While single-speaker phones might not exhibit phase cancellation in the same way, if a phone uses its earpiece and bottom speaker in conjunction for stereo output, reversed polarity in one can introduce similar problems. A faulty battery (e.g., internal short, failing BMS) can trigger OCP/OVP on the phone's motherboard. However, with the right tools, technique, and attention to detail, it is a highly satisfying repair that can restore full functionality to an otherwise unusable smartphone.9. Flex Cable Issue: Theoretically, a damaged flex cable specifically responsible for transmitting touch input from the bottom section of the display to the logic board could cause this localized unresponsiveness. Be extremely cautious not to insert the pick too deeply, as you could damage internal flex cables or components.

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