[SOLVED] I'm looking for LG LMQ610ZM Q7 Prime repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my LG LMQ610ZM Q7 Prime. 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.

@Fred

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 LG LMQ610ZM Q7 Prime 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/542607/A+2.8v+battery+of+Ipad+Mini+1+still+good
Take a look at comment #1688
Also, this : https://xdaforums.com/t/guide-upgrade-downgrade-between-nougat-and-oreo.3752393/.
You can also check this video starting from minute 2:

The LG LMQ610ZM Q7 Prime 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 LG LMQ610ZM Q7 Prime 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 LG LMQ610ZM Q7 Prime 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 LG LMQ610ZM Q7 Prime 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/whompasaurus-rom.2252281/

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

The "System UI isn't responding" error can be disruptive, but by methodically working through these troubleshooting steps, you can typically identify and resolve the underlying software issue. Gently use a plastic prying tool to disconnect the camera module's flex cable from its socket on the motherboard. Checkerboard pattern: Display a black and white checkerboard pattern for some time, then switch to a solid gray. At its core, system file corruption refers to damage or alteration of critical operating system files necessary for the phone's proper functioning. Be meticulous with screw placement, as using a longer screw in a shorter hole can cause damage to the logic board. ESD Protection: Always wear an ESD wrist strap, ensuring it's properly grounded to an anti-static mat. Difficulty Connecting: Device struggles to authenticate or obtain an IP address. Boot into Safe Mode: For Android users, booting into safe mode (which disables all third-party apps) is a critical diagnostic step. Isopropyl Alcohol (IPA) and Cotton Swabs/Lint-Free Wipes: For cleaning. Replace it with a brand new, undamaged pentalobe screw, or a compatible Phillips head screw if it's an internal screw and you have a suitable replacement. It's important to differentiate dust under the display from other common screen anomalies: Bypassing FRP typically involves exploiting specific vulnerabilities in the Android operating system or using specialized tools that communicate with the device. Before proceeding with full reassembly, it's crucial to test the new component. This connection is vital for electromagnetic interference (EMI) shielding, preventing external noise from affecting internal components and containing internal noise from radiating outwards. Thorough research, meticulous preparation, and strict adherence to device-specific guides are paramount for a successful downgrade. Update Carrier Settings: On iOS, go to Settings > General > About and wait for any carrier settings update prompts. Reboot: After "PASS!" appears in Odin, the phone will automatically reboot. Extremely fine needle or thin plastic pick: Even a straight sewing pin is too risky; a very thin plastic probe is preferred. Random Reboots/Crashes: The phone suddenly restarts or powers off without warning. Suction Cup: To help lift the screen (if screen removal is necessary). Carefully reassemble the logic board into the phone, reconnecting all flex cables and components. A hot air rework station with various nozzles, and a fine-tip soldering iron (pencil iron). It demands patience, precision, and a systematic approach, moving beyond simple component swaps to true board-level forensics. NFC Antenna: Usually a sticker-like coil on the back of the device or integrated into the wireless charging coil. These can sometimes partially block the speaker grille, causing muffled sound. Earpiece speaker: Make a normal phone call and hold the phone to your ear. Apply new adhesive: If you have pre-cut adhesive strips, apply them precisely to the edges of the phone frame, following the contours. Purpose: A versatile, clear adhesive (B-7000) or black (T-7000) that cures slowly, allowing for repositioning. Replacing the front panel gasket is therefore essential to restore the device's protection against dust, splashes, and accidental water exposure, thereby extending its lifespan and maintaining its intended durability. Drift causes this integrated angle to continuously accumulate error, moving away from zero.

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