[SOLVED] I'm looking for LG US601 X Series repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my LG US601 X Series. 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.

@Florencia

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 US601 X Series 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/746109/Whirlpool+Duet+Washer+Error+codes
Take a look at comment #1617
Also, this : https://www.ifixit.com/Answers/View/531561/Freezer+is+still+running.
You can also check this video starting from minute 8:

The LG US601 X Series 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 US601 X Series 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 US601 X Series 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 US601 X Series 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/q-any-earth-and-legend-player-here.1588034/

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

Tin Pads (Optional but Recommended): Apply a tiny amount of fresh, lead-free solder to each pad with a fine-tip iron. Always make Nandroid backups in custom recovery (TWRP) before flashing. This can stem from either software corruption or underlying hardware problems. If the phone is stuck in a boot loop, try a forced restart (usually holding Power + Volume Down for 10-15 seconds). Built-in Diagnostic Tools: Many Android phones have hidden diagnostic menus (e.g., dialer codes like #0# on Samsung, ##6484## on Xiaomi, or generic ##4636##). This is a significantly more complex repair, often requiring micro-soldering skills and schematics to diagnose faulty components like power ICs, camera control chips, or even CPU issues affecting the camera bus. Connect to Motherboard: Carefully connect the new volume flex cable to its designated socket on the motherboard. Poor Call Quality: Distorted voice, crackling, or dropped audio during calls. After making any of the above changes, a simple restart can sometimes ensure the settings are fully applied and clear any temporary display rendering glitches. Protective Materials: Soft cloths, microfiber towels, or thin plastic sheets to protect the frame surface during straightening. Precision Tweezers & Vacuum Pickup Tool: For manipulating and lifting the chip. Gently disconnect the vibration motor's flex cable (or the motor itself if it's a direct snap-on) from the motherboard connector. Check if it charges correctly, holds a charge, and functions normally. Flex Cable/Spring Contacts: If the antenna is a flex cable or connects via spring contacts: Identify Camera Module(s): Locate the front and/or rear camera modules. Test Across the Component: Always place the probes on both ends of the fuse itself, not on the surrounding pads or components, to measure its internal resistance/continuity. Gaskets and Light Pipes: These small, often overlooked pieces are vital. In advanced diagnostic scenarios, certain system logs might show errors related to the NFC controller or antenna, though this is less common for end-users to access directly. The process of opening your smartphone varies significantly between models. This is typically a repair best left to professionals, as it involves opening the device and handling delicate components. If temperatures continue to rise, the system may further reduce brightness, slow charging, or even forcibly shut down the device to prevent hardware damage. For smartphone boards, a cleaning solution of 99% IPA or a specialized non-ionic PCB cleaning solution mixed with distilled water is recommended. Component Malfunction: A component (e.g., an IC, connector) that receives power or data through a damaged via will stop working or behave erratically. This guide will walk you through various strategies, from simple software fixes to complex chip-off data extraction, to help you retrieve your precious information. Developer Options (Android): Provides access to CPU usage, running services, background process limits, and other performance monitoring tools. Manufacturers use internal databases to track components by their serial numbers. Their operation is simple yet profoundly effective: a thin wire or filament within the fuse is engineered to melt and break the circuit when the current flowing through it exceeds a predetermined safe limit. While other factors can cause slow speeds, if it's accompanied by other antenna symptoms, it reinforces the suspicion. This is one of the more explicit and robust laws globally regarding IMEI manipulation. Ground: Represented by a specific symbol (three horizontal lines of decreasing length or an inverted triangle).

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