[SOLVED] I'm looking for QUER KOM0701 tablet 7 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my QUER KOM0701 tablet 7. 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.

@James

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 QUER KOM0701 tablet 7 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/q-galaxy-note-stock-keyboard-3x4-layout-problem.1783016/
Take a look at comment #1035
Also, this : https://www.ifixit.com/Wiki/ZTE_Lever_Troubleshooting.
You can also check this video starting from minute 7:

The QUER KOM0701 tablet 7 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 QUER KOM0701 tablet 7 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 QUER KOM0701 tablet 7 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 QUER KOM0701 tablet 7 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/838549/I+need+the+part+no.+for+thr+wifi+board+on+the+tv+model+un46es6100

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

Backup (Crucial): Before a factory reset, try to back up your critical personal data (photos, videos, documents). Water Damage: Exposure to moisture can cause corrosion and short circuits on the audio components, leading to static. Review and disable notifications for apps that don't require immediate alerts. Once these protective layers are compromised, the lens becomes far more susceptible to smudges, reflections, and permanent damage. Even if parts are found, their quality may be questionable, or the device's performance may not justify the effort. Once cool, meticulously clean the area around the newly soldered IC with isopropyl alcohol to remove all flux residue. Compare the reported temperatures with how the device feels to the touch. A fully charged lithium-ion battery can be more volatile if accidentally punctured or shorted. Complete Disassembly: This involves meticulously disassembling the entire smartphone, carefully removing every single component from the old, damaged frame. This is not a repair for beginners, as the risk of irreparable damage to an expensive motherboard is high. All flex cables (display, charging port, cameras, buttons, antenna cables). If photos are still blurry or distorted after replacing the bump, the internal camera module might need replacement. Common `fastboot` commands include `fastboot devices` (to check connection), `fastboot reboot` (to exit Fastboot and reboot normally), `fastboot flash` (to write partitions), and `fastboot oem unlock` (to unlock the bootloader). Diagnosis and Confirmation: A technician uses schematics, multimeters, and specialized diagnostic tools to confirm that the baseband IC itself (or its surrounding power management ICs, filters, and antenna lines) is the culprit, rather than a broken antenna or SIM card reader. Screw Holes/Standoffs: Ensure all internal screw holes and component standoffs are clear and undamaged. Software Glitches: While less common for direct coil overheating, software issues could lead to excessive power draw in background processes that contribute to overall phone heat during charging. Sound Enhancement: Disable any software-based sound enhancements (equalizers, virtual surround sound) temporarily to see if they are causing distortion. They can easily scratch the board, short out pins, or damage the connector. Replacing the board or display might result in "Important Display Message" warnings or loss of True Tone functionality without specialized programmers to transfer display data. Motor Detachment: After a drop, the motor might be visibly loose inside the phone. Ensure the wire is not under tension and will not interfere with other components. If a new, confirmed working display assembly and battery don't resolve the ghost touch, the issue might stem from the touch controller IC on the logic board itself. If it only happens on one network, the problem might be with that specific router or network environment. Diodes: Often used for rectification (converting AC to DC, though less common in primary DC charging paths) or as part of protection circuits. Suction Cup: Often used to assist in safely lifting display assemblies from the phone frame. The chosen location significantly impacts long-term component integrity. The causes of barometer sensor faults can be categorized into software issues and hardware malfunctions, with a unique consideration for the barometer: its reliance on an open port to sense pressure. The loudspeaker is most commonly found at the bottom of the phone, often within a plastic enclosure or part of the charging port assembly. Aerosol cans are convenient, or dedicated spray guns can be used for better control. Flux residue, often seen as a sticky or crusty film around solder joints, is removed with IPA and a brush or lint-free swab.

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